diff --git a/arrow-buffer/src/buffer/boolean.rs b/arrow-buffer/src/buffer/boolean.rs
index aaa86832f692..c8e5144c14cb 100644
--- a/arrow-buffer/src/buffer/boolean.rs
+++ b/arrow-buffer/src/buffer/boolean.rs
@@ -25,6 +25,14 @@ use crate::{
 use std::ops::{BitAnd, BitOr, BitXor, Not};
 
 /// A slice-able [`Buffer`] containing bit-packed booleans
+///
+/// `BooleanBuffer`s can be creating using [`BooleanBufferBuilder`]
+///
+/// # See Also
+///
+/// * [`NullBuffer`] for representing null values in Arrow arrays
+///
+/// [`NullBuffer`]: crate::NullBuffer
 #[derive(Debug, Clone, Eq)]
 pub struct BooleanBuffer {
     buffer: Buffer,
diff --git a/arrow-buffer/src/buffer/null.rs b/arrow-buffer/src/buffer/null.rs
index ec12b885eb5a..a178b3101b4e 100644
--- a/arrow-buffer/src/buffer/null.rs
+++ b/arrow-buffer/src/buffer/null.rs
@@ -19,13 +19,16 @@ use crate::bit_iterator::{BitIndexIterator, BitIterator, BitSliceIterator};
 use crate::buffer::BooleanBuffer;
 use crate::{Buffer, MutableBuffer};
 
-/// A [`BooleanBuffer`] used to encode validity for arrow arrays
+/// A [`BooleanBuffer`] used to encode validity for Arrow arrays
 ///
-/// As per the [Arrow specification], array validity is encoded in a packed bitmask with a
+/// In the [Arrow specification], array validity is encoded in a packed bitmask with a
 /// `true` value indicating the corresponding slot is not null, and `false` indicating
 /// that it is null.
 ///
+/// `NullBuffer`s can be creating using [`NullBufferBuilder`]
+///
 /// [Arrow specification]: https://arrow.apache.org/docs/format/Columnar.html#validity-bitmaps
+/// [`NullBufferBuilder`]: crate::NullBufferBuilder
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct NullBuffer {
     buffer: BooleanBuffer,
@@ -49,7 +52,8 @@ impl NullBuffer {
 
     /// Create a new [`NullBuffer`] of length `len` where all values are valid
     ///
-    /// Note: it is more efficient to not set the null buffer if it is known to be all valid
+    /// Note: it is more efficient to not set the null buffer if it is known to
+    /// be all valid (aka all values are not null)
     pub fn new_valid(len: usize) -> Self {
         Self {
             buffer: BooleanBuffer::new_set(len),
diff --git a/arrow-buffer/src/builder/boolean.rs b/arrow-buffer/src/builder/boolean.rs
index ca178ae5ce4e..67b306dd8cea 100644
--- a/arrow-buffer/src/builder/boolean.rs
+++ b/arrow-buffer/src/builder/boolean.rs
@@ -19,6 +19,12 @@ use crate::{bit_mask, bit_util, BooleanBuffer, Buffer, MutableBuffer};
 use std::ops::Range;
 
 /// Builder for [`BooleanBuffer`]
+///
+/// # See Also
+///
+/// * [`NullBuffer`] for building [`BooleanBuffer`]s for representing nulls
+///
+/// [`NullBuffer`]: crate::NullBuffer
 #[derive(Debug)]
 pub struct BooleanBufferBuilder {
     buffer: MutableBuffer,
diff --git a/arrow-buffer/src/builder/null.rs b/arrow-buffer/src/builder/null.rs
index 298b479e87df..ddbca46f7182 100644
--- a/arrow-buffer/src/builder/null.rs
+++ b/arrow-buffer/src/builder/null.rs
@@ -17,12 +17,16 @@
 
 use crate::{BooleanBufferBuilder, MutableBuffer, NullBuffer};
 
-/// Builder for creating the null bit buffer.
+/// Builder for creating [`NullBuffer`]
+///
+/// # Performance
 ///
 /// This builder only materializes the buffer when we append `false`.
 /// If you only append `true`s to the builder, what you get will be
 /// `None` when calling [`finish`](#method.finish).
-/// This optimization is **very** important for the performance.
+///
+/// This optimization is **very** important for the performance as it avoids
+/// allocating memory for the null buffer when there are no nulls.
 #[derive(Debug)]
 pub struct NullBufferBuilder {
     bitmap_builder: Option<BooleanBufferBuilder>,
diff --git a/object_store/src/aws/builder.rs b/object_store/src/aws/builder.rs
index d29fa782e8ff..29b2eefa8021 100644
--- a/object_store/src/aws/builder.rs
+++ b/object_store/src/aws/builder.rs
@@ -427,7 +427,11 @@ impl AmazonS3Builder {
 
     /// Fill the [`AmazonS3Builder`] with regular AWS environment variables
     ///
-    /// Variables extracted from environment:
+    /// All environment variables starting with `AWS_` will be evaluated. Names must
+    /// match acceptable input to [`AmazonS3ConfigKey::from_str`]. Only upper-case environment
+    /// variables are accepted.
+    ///
+    /// Some examples of variables extracted from environment:
     /// * `AWS_ACCESS_KEY_ID` -> access_key_id
     /// * `AWS_SECRET_ACCESS_KEY` -> secret_access_key
     /// * `AWS_DEFAULT_REGION` -> region
@@ -435,6 +439,7 @@ impl AmazonS3Builder {
     /// * `AWS_SESSION_TOKEN` -> token
     /// * `AWS_CONTAINER_CREDENTIALS_RELATIVE_URI` -> <https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html>
     /// * `AWS_ALLOW_HTTP` -> set to "true" to permit HTTP connections without TLS
+    /// * `AWS_REQUEST_PAYER` -> set to "true" to permit operations on requester-pays buckets.
     /// # Example
     /// ```
     /// use object_store::aws::AmazonS3Builder;