Here is a little more information about some of the references (I haven't actually read or seen all of them so I can't comment on all of them):
This book has a very thorough section on all the details about how stretching works and what different stretching methods to use. It also contains over 300 illustrated stretches as well as various stretching programs for 26 different sports and recreational activities. Each stretching program takes about 20 minutes and illustrates the 12 best stretches for that activity. In my humble opinion, this is the most complete book I was able to find on the subject of stretching (however, Science of Stretching, by the same author, is even more comprehensive). Some of you may prefer Kurz' book to this one, however, since it is more devoted to increasing flexibility.
Science of Stretching
This book explains the scientific basis of stretching and discusses physiology, neurophysiology, mechanics, and psychology as they all relate to stretching. The book makes thorough use of illustrations, charts, diagrams, and figures, and discusses each of its topics in great detail. It then presents guidelines for developing a flexibility program, including over 200 stretching exercises and warm-up drills. I suppose you could think of this book as a "graduate-level version" of Sport Stretch.
This is an excellent book that goes into excruciating detail on just about everything you want to know about stretching. It also contains a variety of stretches and stretching programs and is geared towards achieving maximal flexibility in the shortest possible amount of time. The only problem I found in this book is that some of the discussion gets very technical without giving the reader (in my opinion) sufficient background to fully understand what is being said. I believe that Sport Stretch does a better job of explaining things in a more comprehensible (easily understood) fashion.
Most of the reading material that is devoted to PNF stretching is highly technical. This book attempts to break that trend. It tries to explain the history and principles of PNF without getting too technical, and shows how to perform PNF techniques that are appropriate for healthy people (complete with illustrations and easy-to-follow instructions). This book also contains a chapter which discusses the role of PNF techniques during injury rehabilitation. According to the publisher:
The stretches in Facilitated Stretching are known as CRAC (contract-relax, antagonist-contract) stretches. CRAC stretches are the safest PNF stretches because there is no passive movement -- the athlete performs all of the stretching. Facilitated Stretching contains 29 CRAC stretches, which address most of the major muscle groups: 18 are single-muscle stretches, and 11 use the spiral-diagonal patterns that are the heart of PNF stretching. Once readers have learned these stretching techniques, they will be able to design additional stretches for almost any muscle or muscle group. The book also features many self-stretching techniques that athletes can use to maintain their gains in range of motion.
This is a "course" from HFL which claims that you can achieve "total body flexibility in just 8 minutes a day." It explains and presents two excellent stretching routines: one for increasing flexibility and one for maintaining flexibility. It was the only work that I found which discusses the importance of performing certain stretches in a particular order. It is important to note that there is a significant difference between the printed and videotape versions of this course (aside from price): The printed version has a much more thorough discussion of theory, exercise selection, and exercise order; whereas the stretching routines presented in the videotape are better explained, and more "up to date".
Stretch and Strengthen
This is very good, but the author makes a few mistakes in some places (in particular, she seems to equate the stretch reflex, reciprocal inhibition, and PNF with one another). The book is devoted to static stretching and to performing strengthening exercises of the muscles stretched. Each exercise explains what to do, what not to do, and why. There is also a separate section for diagnosing and correcting some problems that you may encounter during a particular stretch.
Health & Fitness Excellence
Simply put, this is one of the best books available on overall health and fitness. It has two chapters devoted to flexibility training that explain and provide several static and PNF stretches (although it refers to the PNF stretches as tighten-relax stretches). This is not a "fad" book! It uses sound, proven, scientific principles and research (explained in simple terms) to present programs for: reducing stress, strength and flexibility training, nutritional wellness, body fat control, postural vitality, rejuvenation and living environments design, and mind and life unity. I highly recommend this book.
This is a fantastic book of yoga exercises. Each exercise is very well explained along with instructions on what to do if you don't seem to feel the stretch, or think you are feeling it in the wrong place. It is chock-full of useful information and is very well written.
Stretching Without Pain
The author, W. Paul Blakey, is a practicing Osteopath, and former international ballet dancer. The book is very similar in format and content to this document, only it has well over a hundred illustrations, and also covers some additional material not found in this document (such as mental and emotional aspects to stretching and "stretching warzones"). It is one of the best quick, easy, and up-to-date stretching introductions that you will find. I can't think of any other book that is under a hundred pages that covers as much as this book does (including isometric and PNF stretches). For more information about this book, contact Twin Eagles Educational and Healing Institute at http://www.sunshine.net/www/0/sn0016. You can also reach the author by e-mail at TEEHI(at)sunshine.net.
The Muscle Book
The author, Paul Blakey, is a practicing Osteopath, and former international ballet dancer. He has written and illustrated this book to help everyone who needs to know more about their own muscles, and how to look after them. The book clearly identifies the major surface muscles of the human body, and shows how they work. For each muscle there is straightforward information about first aid by massage, and an indication of particular dangers to watch for. All students of physique, and in particular dancers and gymnasts should find this book useful. For more information about this book, contact Twin Eagles Educational and Healing Institute at http://www.sunshine.net/www/0/sn0016. You can also reach the author by e-mail at TEEHI(at)sunshine.net.
Mobility Training for the Martial Arts
This book is also quite good and quite comprehensive, but not as good (in my personal opinion) as Sport Stretch or Stretching Scientifically.
This book is a little old but is wonderfully written (although it could be organized a bit better). It contains information at just about every level of detail about stretching, increasing and maintaining suppleness, and preventing the loss of suppleness. There is also a glossary of terms and concepts near the end of the book.
A lot of people like this one. It presents a wide variety of stretches and stretching routines and does a good job of explaining each one. It does not go into too much detail about stretching other than just to present the various stretches and routines.