diff --git a/geo/CHANGES.md b/geo/CHANGES.md
index 4b7c7895d..2b958d6ad 100644
--- a/geo/CHANGES.md
+++ b/geo/CHANGES.md
@@ -121,6 +121,8 @@
   * <https://github.com/georust/geo/pull/1148>
 * Point in `Triangle` and `Rect` performance improvemnets
   * <https://github.com/georust/geo/pull/1057>
+* Fix crashes in `BooleanOps`
+  * <https://github.com/georust/geo/pull/1234>
 
 ## 0.27.0
 
diff --git a/geo/src/algorithm/bool_ops/i_overlay_integration.rs b/geo/src/algorithm/bool_ops/i_overlay_integration.rs
index fcf3a0a1b..632a3472f 100644
--- a/geo/src/algorithm/bool_ops/i_overlay_integration.rs
+++ b/geo/src/algorithm/bool_ops/i_overlay_integration.rs
@@ -11,6 +11,7 @@ pub trait BoolOpsCoord<T>: Copy {
     fn y(&self) -> T;
 }
 
+/// A geometry coordinate number suitable for performing geometric boolean operations.
 pub trait BoolOpsNum: GeoNum {
     type CoordType: BoolOpsCoord<Self>;
     type OverlayType: BoolOpsOverlay<CoordType = Self::CoordType>;
diff --git a/geo/src/algorithm/bool_ops/mod.rs b/geo/src/algorithm/bool_ops/mod.rs
index f0391a1ad..16287b049 100644
--- a/geo/src/algorithm/bool_ops/mod.rs
+++ b/geo/src/algorithm/bool_ops/mod.rs
@@ -29,6 +29,13 @@ use crate::geometry::{LineString, MultiLineString, MultiPolygon, Polygon};
 pub trait BooleanOps {
     type Scalar: BoolOpsNum;
 
+    /// The exterior and interior rings of the geometry.
+    ///
+    /// It doesn't particularly matter which order they are in, as the topology algorithm counts crossings
+    /// to determine the interior and exterior of the polygon.
+    ///
+    /// It is required that the rings are from valid geometries, that the rings not overlap.
+    /// In the case of a MultiPolygon, this requires that none of its polygon's interiors may overlap.
     fn rings(&self) -> impl Iterator<Item = &LineString<Self::Scalar>>;
 
     fn boolean_op(