Pathfinder RPG Bestiary Pocket Edition - Rules of Play says:

This brilliant Pocket size edition of the Pathfinder Core Rules is a copy of the original in layout and format just in a more compact size, so you still get the wealth of information that would get in the big version but you may need some new reading glasses!

The Pathfinder RPG Bestiary Pocket Edition includes:

• More than 350 different monsters
• Dozens of monstrous variants to modify creatures and keep players on their toes
• Numerous lists of monsters to aid in navigation, including lists by Challenge Rating, monster type, and habitat
• Extensive rules for creating effective and balanced monsters
• Rules for advancing monsters by hit dice, template, or class level
• Universal monster rules to simplify special attacks, defenses, and qualities like breath weapons, damage reduction, and regeneration
• More than a dozen feats tailored especially for monsters
• Suggestions for monstrous cohorts
• Two dozen additional animal companions
• More than a dozen different wandering monster encounter tables