diff --git a/fastfield_codecs/src/lib.rs b/fastfield_codecs/src/lib.rs
index 1204dd6b0..78b5322b4 100644
--- a/fastfield_codecs/src/lib.rs
+++ b/fastfield_codecs/src/lib.rs
@@ -63,6 +63,7 @@ pub trait FastFieldDataAccess {
 }
 
 #[derive(Debug, Clone)]
+/// Contains statistics used for compression in field writing.
 pub struct FastFieldStats {
     pub min_value: u64,
     pub max_value: u64,
diff --git a/src/fastfield/alive_bitset.rs b/src/fastfield/alive_bitset.rs
index bea0120fd..cc2a93643 100644
--- a/src/fastfield/alive_bitset.rs
+++ b/src/fastfield/alive_bitset.rs
@@ -7,7 +7,7 @@ use ownedbytes::OwnedBytes;
 use crate::space_usage::ByteCount;
 use crate::DocId;
 
-/// Write a alive `BitSet`
+/// Write an alive `BitSet`
 ///
 /// where `alive_bitset` is the set of alive `DocId`.
 /// Warning: this function does not call terminate. The caller is in charge of
@@ -55,7 +55,7 @@ impl AliveBitSet {
         AliveBitSet::from(readonly_bitset)
     }
 
-    /// Opens a delete bitset given its file.
+    /// Opens an alive bitset given its file.
     pub fn open(bytes: OwnedBytes) -> AliveBitSet {
         let bitset = ReadOnlyBitSet::open(bytes);
         AliveBitSet::from(bitset)
@@ -79,13 +79,13 @@ impl AliveBitSet {
         self.bitset.iter()
     }
 
-    /// Get underlying bitset
+    /// Get underlying bitset.
     #[inline]
     pub fn bitset(&self) -> &ReadOnlyBitSet {
         &self.bitset
     }
 
-    /// The number of deleted docs
+    /// The number of alive documents.
     pub fn num_alive_docs(&self) -> usize {
         self.num_alive_docs
     }
diff --git a/src/fastfield/bytes/writer.rs b/src/fastfield/bytes/writer.rs
index 91f74adf9..2a98c1c08 100644
--- a/src/fastfield/bytes/writer.rs
+++ b/src/fastfield/bytes/writer.rs
@@ -7,7 +7,7 @@ use crate::DocId;
 
 /// Writer for byte array (as in, any number of bytes per document) fast fields
 ///
-/// This `BytesFastFieldWriter` is only useful for advanced user.
+/// This `BytesFastFieldWriter` is only useful for advanced users.
 /// The normal way to get your associated bytes in your index
 /// is to
 /// - declare your field with fast set to `Cardinality::SingleValue`
diff --git a/src/fastfield/mod.rs b/src/fastfield/mod.rs
index f864e8d4e..9c780c893 100644
--- a/src/fastfield/mod.rs
+++ b/src/fastfield/mod.rs
@@ -2,7 +2,7 @@
 //!
 //! It is the equivalent of `Lucene`'s `DocValues`.
 //!
-//! Fast fields is a column-oriented fashion storage of `tantivy`.
+//! A fast field is a column-oriented fashion storage for `tantivy`.
 //!
 //! It is designed for the fast random access of some document
 //! fields given a document id.
@@ -12,8 +12,8 @@
 //!
 //!
 //! Fields have to be declared as `FAST` in the  schema.
-//! Currently only 64-bits integers (signed or unsigned) are
-//! supported.
+//! Currently supported fields are: u64, i64 and f64.
+//! u8 are supported for advanced usage.
 //!
 //! They are stored in a bit-packed fashion so that their
 //! memory usage is directly linear with the amplitude of the
diff --git a/src/fastfield/multivalued/writer.rs b/src/fastfield/multivalued/writer.rs
index d94a0bf6f..a848ee65d 100644
--- a/src/fastfield/multivalued/writer.rs
+++ b/src/fastfield/multivalued/writer.rs
@@ -14,7 +14,7 @@ use crate::DocId;
 /// Writer for multi-valued (as in, more than one value per document)
 /// int fast field.
 ///
-/// This `Writer` is only useful for advanced user.
+/// This `Writer` is only useful for advanced users.
 /// The normal way to get your multivalued int in your index
 /// is to
 /// - declare your field with fast set to `Cardinality::MultiValues`
@@ -23,10 +23,11 @@ use crate::DocId;
 ///
 /// The `MultiValuedFastFieldWriter` can be acquired from the
 /// fastfield writer, by calling
-/// [`.get_multivalue_writer(...)`](./struct.FastFieldsWriter.html#method.get_multivalue_writer).
+/// [`.get_multivalue_writer_mut(...)`](./struct.FastFieldsWriter.html#method.
+/// get_multivalue_writer_mut).
 ///
-/// Once acquired, writing is done by calling calls to
-/// `.add_document_vals(&[u64])` once per document.
+/// Once acquired, writing is done by calling
+/// [`.add_document_vals(&[u64])`](MultiValuedFastFieldWriter::add_document_vals) once per document.
 ///
 /// The serializer makes it possible to remap all of the values
 /// that were pushed to the writer using a mapping.
diff --git a/src/fastfield/serializer/mod.rs b/src/fastfield/serializer/mod.rs
index b138689d9..cc5329730 100644
--- a/src/fastfield/serializer/mod.rs
+++ b/src/fastfield/serializer/mod.rs
@@ -197,7 +197,7 @@ impl CompositeFastFieldSerializer {
 
     /// Closes the serializer
     ///
-    /// After this call the data must be persistently save on disk.
+    /// After this call the data must be persistently saved on disk.
     pub fn close(self) -> io::Result<()> {
         self.composite_write.close()
     }
diff --git a/src/fastfield/writer.rs b/src/fastfield/writer.rs
index 34bc9099d..6d19ed5f8 100644
--- a/src/fastfield/writer.rs
+++ b/src/fastfield/writer.rs
@@ -14,7 +14,7 @@ use crate::postings::UnorderedTermId;
 use crate::schema::{Cardinality, Document, Field, FieldEntry, FieldType, Schema};
 use crate::termdict::TermOrdinal;
 
-/// The fastfieldswriter regroup all of the fast field writers.
+/// The `FastFieldsWriter` regroups all of the fast field writers.
 pub struct FastFieldsWriter {
     single_value_writers: Vec<IntFastFieldWriter>,
     multi_values_writers: Vec<MultiValuedFastFieldWriter>,