I procrastinate from my studies (working toward my Doctor of Physical Therapy degree) guilt-free when I pour over The Key Muscles of Hatha Yoga.  Other anatomy and yoga books, DVDs, etc. have left me wanting more (usually more clear instruction), but this book rocks my world and puts my brain cells to work linking postures and movement and energies. Love it. If you have an interest in anatomy and yoga I highly recommend buying this book as you’ll want it for reference for years to come.