diff --git a/src/components/Book/Book.tsx b/src/components/Book/Book.tsx
index 3b79bbf..129e817 100644
--- a/src/components/Book/Book.tsx
+++ b/src/components/Book/Book.tsx
@@ -138,7 +138,7 @@ const Book: React.FC<PropsWithChildren<BookProps>> = (props): React.JSX.Element
         '--crease-margin': ((wrapperSize?.width || 0) * (props.creaseMargin ?? defaults.creaseMargin)).toFixed(2) + 'px',
         '--crease-width': ((wrapperSize?.width || 0) * (props.creaseWidth ?? defaults.creaseWidth)).toFixed(2) + 'px',
         '--thickness': ((wrapperSize?.height || 0) * (props.thickness ?? defaults.thickness)).toFixed(2) + 'px',
-        '--cover-margin': ((wrapperSize?.height || 0) * (props.coverMargin ?? defaults.coverMargin)).toFixed(2) + 'px',
+        '--cover-margin': ((wrapperSize?.width || 0) * (props.coverMargin ?? defaults.coverMargin)).toFixed(2) + 'px',
 
         '--fallback-color': props.coverColor,
         '--transition-duration': props.transitionDuration,
diff --git a/src/components/Book/Book.types.ts b/src/components/Book/Book.types.ts
index de3806f..6501a80 100644
--- a/src/components/Book/Book.types.ts
+++ b/src/components/Book/Book.types.ts
@@ -27,7 +27,7 @@ export interface BookProps {
 	 */
 	thickness?: number;
 	/**
-	 * Cover margin, relative to the height of the book. `0` - `1`
+	 * Cover margin, relative to the width of the book. `0` - `1`
 	 */
 	coverMargin?: number;