This guidebook to board membership lays out three broad lines of questioning that every board candidate should explore before saying “yes” or “no” to an invitation to join. The three clusters of questions include: (1) those that make or break the opportunity; (2) those that explore the relative hygiene or well-being of the board inviting you to join; and (3) those that distinguish merely good boards from the practices of those boards that can be said to be great.