On your first turn in Combat facing a new enemy, you may use a Free Action to make an Intelligence (Arcana, History, Religion, or Nature as appropriate) to ascertain knowledge about your foe. The DC equals 10 + the creature's CR. For every 5 above the CR, you learn an extra bit of information. See the following tables for more information.
Enemy types and the check they fall under are as follows:
Arcana:
Abberations, Constructs, Dragons, Monstrosities, Oozes
History:
Giants, Humanoids
Religion:
Celestial, Fiend, Undead
Nature:
Beast, Elemental, Fey, Plant
Possible information to glean is as follows:
Number of Hit Dice
Best/Worst Saving Throw
Skills
Weaknesses
Resistances/Immunities
Special Senses
Special Abilities
Special Attacks
Number of Attacks
Attack Damage Type
Comments