diff --git a/.gitignore b/.gitignore
index cbbffb0..854fcb5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@ nimcache/
 tests/packagetest/packagetest
 src/leveldb
 tests/test
+src/htmldocs/
diff --git a/README.md b/README.md
index d54a1e1..8ced596 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,46 @@
 # leveldb.nim
-LevelDB wrapper for Nim
+A LevelDB wrapper for Nim in a Nim friendly way.
+
+Create a database:
+```Nim
+   import leveldb
+   import options
+
+   var db = leveldb.open("/tmp/mydata")
+```
+
+Read or modify the database content:
+```Nim
+   assert db.getOrDefault("nothing", "") == ""
+
+   db.put("hello", "world")
+   db.put("bin", "GIF89a\1\0")
+   echo db.get("hello")
+   assert db.get("hello").isSome()
+
+   var key, val = ""
+   for key, val in db.iter():
+     echo key, ": ", repr(val)
+
+   db.delete("hello")
+   assert db.get("hello").isNone()
+```
+
+Batch writes:
+```Nim
+   let batch = newBatch()
+   for i in 1..10:
+     batch.put("key" & $i, $i)
+   batch.delete("bin")
+   db.write(batch)
+```
+
+Iterate over subset of database content:
+```Nim
+   for key, val in db.iterPrefix(prefix = "key1"):
+     echo key, ": ", val
+   for key, val in db.iter(seek = "key3", reverse = true):
+     echo key, ": ", val
+
+   db.close()
+```
diff --git a/src/leveldb.nim b/src/leveldb.nim
index 1303259..b09794d 100644
--- a/src/leveldb.nim
+++ b/src/leveldb.nim
@@ -1,3 +1,56 @@
+## A LevelDB_ wrapper for Nim in a Nim friendly way.
+##
+## LevelDB is a fast and simple key/value data storage library built
+## by Google that provides an ordered mapping from string keys to
+## string values.
+##
+## .. _LevelDB: https://github.com/google/leveldb
+##
+## Create a database:
+##
+## .. code-block:: Nim
+##    import leveldb
+##    import options
+##
+##    var db = leveldb.open("/tmp/mydata")
+##
+## Read or modify the database content:
+##
+## .. code-block:: Nim
+##
+##    assert db.getOrDefault("nothing", "") == ""
+##
+##    db.put("hello", "world")
+##    db.put("bin", "GIF89a\1\0")
+##    echo db.get("hello")
+##    assert db.get("hello").isSome()
+##
+##    var key, val = ""
+##    for key, val in db.iter():
+##      echo key, ": ", repr(val)
+##
+##    db.delete("hello")
+##    assert db.get("hello").isNone()
+##
+## Batch writes:
+##
+## .. code-block:: Nim
+##    let batch = newBatch()
+##    for i in 1..10:
+##      batch.put("key" & $i, $i)
+##    batch.delete("bin")
+##    db.write(batch)
+##
+## Iterate over subset of database content:
+##
+## .. code-block:: Nim
+##    for key, val in db.iterPrefix(prefix = "key1"):
+##      echo key, ": ", val
+##    for key, val in db.iter(seek = "key3", reverse = true):
+##      echo key, ": ", val
+##
+##    db.close()
+
 import options, os, strutils
 import leveldb/raw
 
@@ -5,15 +58,19 @@ type
   LevelDb* = ref object
     path*: string
     db: ptr leveldb_t
+    cache: ptr leveldb_cache_t
+    readOptions: ptr leveldb_readoptions_t
     syncWriteOptions: ptr leveldb_writeoptions_t
     asyncWriteOptions: ptr leveldb_writeoptions_t
-    readOptions: ptr leveldb_readoptions_t
-    cache: ptr leveldb_cache_t
 
-  LevelDbBatch* = ref object
+  LevelDbWriteBatch* = ref object
+    ## Write batches for bulk data modification.
     batch: ptr leveldb_writebatch_t
 
   CompressionType* = enum
+    ## No compression or using Snappy_ algorithm (default).
+    ##
+    ## .. _Snappy: http://google.github.io/snappy/
     ctNoCompression = leveldb_no_compression,
     ctSnappyCompression = leveldb_snappy_compression
 
@@ -49,10 +106,15 @@ proc checkError(errPtr: cstring) =
     raise newException(LevelDbException, $errPtr)
 
 proc getLibVersion*(): (int, int) =
+  ## Get the version of leveldb C library.
   result[0] = leveldb_major_version()
   result[1] = leveldb_minor_version()
 
 proc close*(self: LevelDb) =
+  ## Closes the database.
+  ##
+  ## See also:
+  ## * `open proc <#open%2Cstring%2Cint%2Cint%2Cint>`_
   if self.db == nil:
     return
   leveldb_close(self.db)
@@ -69,6 +131,12 @@ proc open*(path: string, create = true, reuse = true, paranoidChecks = true,
     cacheCapacity = 0, blockSize = 4 * 1024, writeBufferSize = 4*1024*1024,
     maxOpenFiles = 1000, maxFileSize = 2 * 1024 * 1024,
     blockRestartInterval = 16): LevelDb =
+  ## Opens a database.
+  ##
+  ## Raises `LevelDbException` if corruption detected in the database.
+  ##
+  ## See also:
+  ## * `close proc <#close%2CLevelDb>`_
   new(result, close)
 
   let options = leveldb_options_create()
@@ -111,7 +179,20 @@ proc open*(path: string, create = true, reuse = true, paranoidChecks = true,
   result.db = leveldb_open(options, path, addr errPtr)
   checkError(errPtr)
 
-proc put*(self: LevelDb, key: string, value: string, sync = true) =
+proc put*(self: LevelDb, key: string, value: string, sync = false) =
+  ## Set a `value` for the specified `key`.
+  ##
+  ## By default, `sync` is turned off, each write to leveldb is asynchronous.
+  ## Unless reboot, a crash of just the writing process will not cause any
+  ## loss since even when `sync` is false.
+  ##
+  ## See also:
+  ## * `put proc <#put%2CLevelDbWriteBatch%2Cstring%2Cstring>`_
+  runnableExamples:
+    let db = leveldb.open("/tmp/test")
+    db.put("hello", "world")
+    db.close()
+
   assert self.db != nil
   var errPtr: cstring = nil
   let writeOptions = if sync: self.syncWriteOptions else: self.asyncWriteOptions
@@ -127,6 +208,16 @@ proc newString(cstr: cstring, length: csize): string =
     result = ""
 
 proc get*(self: LevelDb, key: string): Option[string] =
+  ## Get the value for the specified `key`.
+  ##
+  ## See also:
+  ## * `getOrDefault proc <#getOrDefault%2CLevelDb%2Cstring>`_
+  runnableExamples:
+    let db = leveldb.open("/tmp/test")
+    db.put("hello", "world")
+    echo db.get("hello")
+    db.close()
+
   var size: csize
   var errPtr: cstring = nil
   let s = leveldb_get(self.db, self.readOptions, key, key.len, addr size, addr errPtr)
@@ -138,35 +229,104 @@ proc get*(self: LevelDb, key: string): Option[string] =
     result = some(newString(s, size))
     free(s)
 
-proc delete*(self: LevelDb, key: string, sync = true) =
+proc getOrDefault*(self: LevelDb, key: string, default = ""): string =
+  ## Get the value for the specified `key`, or `default` if no value was set.
+  ##
+  ## See also:
+  ## * `get proc <#get%2CLevelDb%2Cstring>`_
+  runnableExamples:
+    let db = leveldb.open("/tmp/test")
+    doAssert db.getOrDefault("what?", "nothing") == "nothing"
+    db.close()
+
+  let val = self.get(key)
+  if val.isNone():
+    result = default
+  else:
+    result = val.get()
+
+proc delete*(self: LevelDb, key: string, sync = false) =
+  ## Delete the key/value pair for the specified key.
+  ##
+  ## See also:
+  ## * `delete proc <#delete%2CLevelDbWriteBatch%2Cstring>`_
   var errPtr: cstring = nil
   let writeOptions = if sync: self.syncWriteOptions else: self.asyncWriteOptions
   leveldb_delete(self.db, writeOptions, key, key.len, addr errPtr)
   checkError(errPtr)
 
-proc destroy*(self: LevelDbBatch) =
+proc destroy*(self: LevelDbWriteBatch) =
+  ## Destroys this batch.
+  ##
+  ## See also:
+  ## * `newBatch proc <#newBatch>`_
   if self.batch == nil:
     return
   leveldb_writebatch_destroy(self.batch)
   self.batch = nil
 
-proc newBatch*(): LevelDbBatch =
+proc newBatch*(): LevelDbWriteBatch =
+  ## Creates a new database write batch.
+  ##
+  ## See also:
+  ## * `write proc <#write%2CLevelDb%2CLevelDbWriteBatch>`_
+  ## * `put proc <#put%2CLevelDbWriteBatch%2Cstring%2Cstring>`_
+  ## * `delete proc <#delete%2CLevelDbWriteBatch%2Cstring>`_
+  ## * `append proc <#append%2CLevelDbWriteBatch%2CLevelDbWriteBatch>`_
+  ## * `clear proc <#clear%2CLevelDbWriteBatch>`_
+  ## * `destroy proc <#destroy%2CLevelDbWriteBatch>`_
+
+  runnableExamples:
+    let db = leveldb.open("/tmp/test")
+    let batch = newBatch()
+    for i in 1..10:
+      batch.put("key" & $i, $i)
+    batch.delete("another")
+    db.write(batch)
+    db.close()
+
   new(result, destroy)
   result.batch = leveldb_writebatch_create()
 
-proc put*(self: LevelDbBatch, key: string, value: string, sync = true) =
+proc put*(self: LevelDbWriteBatch, key: string, value: string, sync = false) =
+  ## Set a `value` for the specified `key`.
+  ## Same as `put <#put%2CLevelDb%2Cstring%2Cstring>`_ but operates on the
+  ## write batch instead.
+  ##
+  ## See also:
+  ## * `put proc <#put%2CLevelDb%2Cstring%2Cstring>`_
+  ## * `newBatch proc <#newBatch>`_
   leveldb_writebatch_put(self.batch, key, key.len.csize, value, value.len.csize)
 
-proc append*(self, source: LevelDbBatch) =
+proc append*(self, source: LevelDbWriteBatch) =
+  ## Merges the `source` batch into this batch.
+  ##
+  ## See also:
+  ## * `newBatch proc <#newBatch>`_
   leveldb_writebatch_append(self.batch, source.batch)
 
-proc delete*(self: LevelDbBatch, key: string) =
+proc delete*(self: LevelDbWriteBatch, key: string) =
+  ## Delete the key/value pair for the specified `key`.
+  ## Same as `delete <#delete%2CLevelDb%2Cstring>`_ but operates on the
+  ## write batch instead.
+  ##
+  ## See also:
+  ## * `delete proc <#delete%2CLevelDb%2Cstring>`_
+  ## * `newBatch proc <#newBatch>`_
   leveldb_writebatch_delete(self.batch, key, key.len.csize)
 
-proc clear*(self: LevelDbBatch) =
+proc clear*(self: LevelDbWriteBatch) =
+  ## Clear all updates buffered in this batch.
+  ##
+  ## See also:
+  ## * `newBatch proc <#newBatch>`_
   leveldb_writebatch_clear(self.batch)
 
-proc write*(self: LevelDb, batch: LevelDbBatch) =
+proc write*(self: LevelDb, batch: LevelDbWriteBatch) =
+  ## Write apply the given `batch` to the database.
+  ##
+  ## See also:
+  ## * `newBatch proc <#newBatch>`_
   var errPtr: cstring = nil
   leveldb_write(self.db, self.syncWriteOptions, batch.batch, addr errPtr)
   checkError(errPtr)
@@ -183,6 +343,14 @@ proc getIterData(iterPtr: ptr leveldb_iterator_t): (string, string) =
 
 iterator iter*(self: LevelDb, seek: string = "", reverse: bool = false): (
     string, string) =
+  ## Iterate all key/value pairs in the database from the first one or
+  ## the specified key `seek`.
+  ## By default, the ordering will be lexicographic byte-wise ordering
+  ## with leveldb builtin comparator, unless `reverse` set to `true`.
+  ##
+  ## See also:
+  ## * `iterPrefix iterator <#iterPrefix.i%2CLevelDb%2Cstring>`_
+  ## * `iterRange iterator <#iterRange.i%2CLevelDb%2Cstring%2Cstring>`_
   var iterPtr = leveldb_create_iterator(self.db, self.readOptions)
   defer: leveldb_iter_destroy(iterPtr)
 
@@ -210,6 +378,11 @@ iterator iter*(self: LevelDb, seek: string = "", reverse: bool = false): (
       leveldb_iter_next(iterPtr)
 
 iterator iterPrefix*(self: LevelDb, prefix: string): (string, string) =
+  ## Iterate subset key/value pairs in the database with a particular `prefix`.
+  ##
+  ## See also:
+  ## * `iter iterator <#iter.i%2CLevelDb%2Cstring%2Cbool>`_
+  ## * `iterRange iterator <#iterRange.i%2CLevelDb%2Cstring%2Cstring>`_
   for key, value in iter(self, prefix, reverse = false):
     if key.startsWith(prefix):
       yield (key, value)
@@ -217,6 +390,12 @@ iterator iterPrefix*(self: LevelDb, prefix: string): (string, string) =
       break
 
 iterator iterRange*(self: LevelDb, start, limit: string): (string, string) =
+  ## Yields all key/value pairs between the `start` and `limit` keys
+  ## (inclusive) in the database.
+  ##
+  ## See also:
+  ## * `iter iterator <#iter.i%2CLevelDb%2Cstring%2Cbool>`_
+  ## * `iterPrefix iterator <#iterPrefix.i%2CLevelDb%2Cstring>`_
   let reverse: bool = limit < start
   for key, value in iter(self, start, reverse = reverse):
     if reverse:
@@ -228,12 +407,14 @@ iterator iterRange*(self: LevelDb, start, limit: string): (string, string) =
     yield (key, value)
 
 proc removeDb*(name: string) =
+  ## Remove the database `name`.
   var err: cstring = nil
   let options = leveldb_options_create()
   leveldb_destroy_db(options, name, addr err)
   checkError(err)
 
 proc repairDb*(name: string) =
+  ## Repairs the corrupted database `name`.
   let options = leveldb_options_create()
   leveldb_options_set_create_if_missing(options, levelDbFalse)
   leveldb_options_set_error_if_exists(options, levelDbFalse)
diff --git a/src/leveldb/raw.nim b/src/leveldb/raw.nim
index 7b2ffa8..cae7c85 100644
--- a/src/leveldb/raw.nim
+++ b/src/leveldb/raw.nim
@@ -27,10 +27,10 @@
 ##   be true on entry:
 ## errptr == NULL
 ## errptr points to a malloc()ed null-terminated error message
-##        (On Windows, *errptr must have been malloc()-ed by this library.)
-##   On success, a leveldb routine leaves *errptr unchanged.
-##   On failure, leveldb frees the old value of *errptr and
-##   set *errptr to a malloc()ed error message.
+##        (On Windows, \*errptr must have been malloc()-ed by this library.)
+##   On success, a leveldb routine leaves \*errptr unchanged.
+##   On failure, leveldb frees the old value of \*errptr and
+##   set \*errptr to a malloc()ed error message.
 ##
 ##   (4) Bools have the type uint8_t (0 == false; rest == true)
 ##
@@ -66,7 +66,7 @@ proc leveldb_delete*(db: ptr leveldb_t; options: ptr leveldb_writeoptions_t;
 proc leveldb_write*(db: ptr leveldb_t; options: ptr leveldb_writeoptions_t;
                    batch: ptr leveldb_writebatch_t; errptr: ptr cstring) {.importc.}
 ##  Returns NULL if not found.  A malloc()ed array otherwise.
-##    Stores the length of the array in *vallen.
+##    Stores the length of the array in \*vallen.
 
 proc leveldb_get*(db: ptr leveldb_t; options: ptr leveldb_readoptions_t; key: cstring;
                  keylen: csize; vallen: ptr csize; errptr: ptr cstring): cstring {.importc.}
diff --git a/tests/test.nim b/tests/test.nim
index dad2a3a..4b5b7ab 100644
--- a/tests/test.nim
+++ b/tests/test.nim
@@ -65,6 +65,9 @@ suite "leveldb":
     db.put("hello", "world")
     check(db.get("hello") == some("world"))
 
+  test "get or default":
+    check(db.getOrDefault("nothing", "yes") == "yes")
+
   test "delete":
     db.put("hello", "world")
     db.delete("hello")