These are two of Eddie Bravo's three books he wrote.  These books outline a vast portion of his game.  With many full color pictures and full descriptions for many techniques inside.  Each book is over 300 pages long, with very little filler.  The techniques called the Rubber Guard and the Twister are what are most focused upon in people's eyes and what Eddie is best known for.  However in Mastering The Rubber Guard Eddie explains his half guard game, which is the most important and next level part of his whole system, as well as the spider's web position, something you never want to find yourself in, his favorite butterfly guard sweeps and setups and many added techniques for mixed martial arts.  His Mastering The Twister also contains his mount control position and his back control position with many transitions between these positions and transitions into his spider's web position from these positions as well as many further techniques for mixed martial arts competition.