Provided by CCIDC:
The “Official” IDEX® California Study Guide 
A free booklet prepared by CCIDC. Provides background information on the IDEX® California exam, including the schedule, rules, release of results, exam format, content, sample questions and an FAQ (not intended to be a ‘study manual’).

Provided by Third-Party Vendors:
For study materials and classes, please refer to a list of third-party vendors on the CCIDC website, under the Candidates menu – IDEX® California Exam Information.
Third-Party Disclaimer