This document discusses the types of inter partes proceedings before the Trademark Trial and Appeal Board, including oppositions, cancellations, interferences, and concurrent use proceedings. It provides details on who may file an opposition or petition to cancel a trademark registration and the required timing and procedures for doing so. Key points covered include the difference between opposing a mark's registration versus petitioning to cancel a registered mark, as well as the fees, forms, and other requirements for commencing these proceedings.