Book excerpt: While the terms used to describe the tracery of medieval church windows are familiar (Early English, Decorated, Perpendicular), there has been no really detailed attempt to examine it as a distinct, stylistic architectural form, a gap which this book seeks to address. Based upon a visual catalogue of over 250 images of surviving types and styles from churches throughout England, it traces the progression of ideas and the continuity of motifs and themes in tracery patterns from the thirteenth to the sixteenth centuries, showing how different themes emerged within the main architectural styles; it also looks at the distinction between a window's architectural form and its tracery style, and describes the several different tracery techniques. The volume is completed with a detailed glossary. Stephen Hart is a retired architect, and the author of numerous works, including Flint Flushwork.