Your character has to meet certain requirements before it can join any of these Prestige Classes. The requirements are listed after each link.
Arcane Archer: An arcane spellcaster who draws upon ancient elven traditions to infuse his arrows with potent magical power.
Arcane Trickster: A troublemaker and a scoundrel who uses arcane magic to enhance her thievery and trickery.
Assassin: A remorseless murderer who kills for money and the sheer thrill of death-dealing. (Note that evil characters are not allowed as Guild characters because evil characters are supposed to betray and kill each other. So you can be an Assassin, but you don’t have to be evil or assassinate someone to do so. –Grandmaster)
Battle Herald: A veteran whose masterful tactics and air of command inspire allies to greater feats of heroism.
Dragon Disciple: An arcane spellcaster who has embraced his latent draconic heritage and, over the course of training and devotion, undergoes a partial transformation into a dragon.
Duelist: A swashbuckling swordfighter who relies upon grace, poise, and acrobatics to win the day.
Eldritch Knight: An arcane spellcaster who augments his magical skills with combat to create a deadly combination of weapons and magic.
Holy Vindicator: A pious warrior who spreads religion at the edge of a sword.
Horizon Walker: A scout and wanderer comfortable in even the strangest terrain.
Loremaster: A spellcaster who devotes his life to research and rumination upon the mysteries of the world.
Master Chymist: An alchemist whose mutagens create an alternate, brutish personality.
Master Spy: An espionage expert specializing in disguises and striking swiftly from the shadows.
Mystic Theurge: Equally devoted to divine and arcane magic, the mystic theurge combines both magical traditions into one incredibly diverse class.
Nature Warden: A master of the wilderness bonded spiritually to a fearsome animal companion.
Pathfinder Chronicler: An explorer at heart, the Pathfinder chronicler travels to distant, exotic lands to expand her knowledge of the world.
Rage Prophet: A bold and barbaric champion who embraces otherworldly powers in order to perfect the art of combat.
Shadowdancer: A mysterious adventurer who walks the boundaries between the real world and the realm of shadows, and who can command shadows to do her bidding.
Stalwart Defender: A master of defending territory and holding the line at all costs.