From the introduction: Strange Aeons is the first of many planned genre expansions for use with Core Elements. This revision of the original Strange Aeons fine tunes the sanity rules found in the previous releases, and adds some much needed clarification to the rules for sorcery. Like previous editions of Strange Aeons, the entirety of this release is OGC with the exception of the title. Strange Aeons can be used with either Core Elements or in conjunction with other OGL products of your choice. That said, however you ultimately choose to use the revised edition of Strange Aeons, I hope that you enjoy it.