Ashley is usually considered the bible of knots but this handbook is an excellent reference for anyone wanting some instruction on how to tie knots for specific purposes, along with great illustrations. Actually most of the images are very good photos with any knots that join more than one rope showing them in contrasting colors for clarity. ( )

This is a paperback book of 100+ useful and decorative knots. It's a Dorling-Kindersley book, so the photographs are clear, appropriate, and large. The notes are very good, the index is useful, and I chose it over many other knot books. At $17, it's cheap, too. ( )