Rule 23(c)(4) states that, “[w]hen appropriate, an action may be brought or maintained as a class action with respect to particular issues.”  But do classes under Rule 23(c)(4), otherwise known as “issue classes,” also need to satisfy the requirements of Rule 23(a) and (b)?  In Harris v. Medical Transportation Management, Inc., 2023 WL 4567258 (D.C. Cir. July 18, 2023), the D.C. Circuit confirmed that the answer is “yes.”