This question-and-answer-style document describes the policy and process of implementing and enforcing prerequisite and corequisite courses in California community colleges. Prerequisites are defined as a condition of enrollment that students are required to meet prior to enrollment in particular courses and programs. A prerequisite signifies that the skills or body of prior-knowledge required for a course is essential in ensuring a student's success and possibly safety in a particular course. This document systematically provides answers about when course prerequisites should be required, who should be responsible for ensuring that students in classes have met prerequisites, who should have the power to waive a prerequisite, and what are acceptable grades in a prerequisite class. Colleges can assess which courses should have a prerequisite using historical data on student performance and student completion/non-completion rates. Colleges may use assessment test scores or test score ranges to determine if perquisite courses, particularly in basic skills, are needed. While one successful test score cannot be used as a prerequisite, one or more tests may be considered to assess a student's readiness for a particular course. Finally, the document addresses the implications of prerequisites for academic freedom and inquiry. (AF)