Just a note for those that may be new to OGL or D20 games.
If you notice in most third party d20 books they will describe how they present Open Content at the beginning of the book, often setting it in a different font, size, color or even boxed by itself. WotC books with the exception of Unearthed Arcana (and maybe some others), do not contain Open Content. Rather the open content of these books are defined in the SRD.
The SRD is the definition of Open Game Content for d20 books released by Wizards of the Coast. As such, they are not complete rulesets. They are the rules that can be freely copied and used by other publishers in OGL and D20 game books. The missing portions are not really missing, they are just content that is not available for other publishers to reprint.
However, the SRD is useful for previewing the rules of the game before you buy, or as a quick and easy rules reference when you dont have your book handy. This use of the SRD is by no means wrong.
Among the things you wont find in the SRD.
Point Buy for ability scores.
XP awards for CR.
XP to reach a level.
Many aspects of creating and advancing a character.
