While in A-G v Blake [2001] 1 AC 268 the House of Lords made it clear that an account of profits could be awarded in the context of a breach of contract, it failed to indicate precisely when or why this would be appropriate. The starting point has generally been the statement by Lord Nicholls of Birkenhead in that case, that an account of profits should be awarded only in “exceptional cases” and that “a useful general guide” is whether the claimant had “a legitimate interest in preventing the defendant’s profit-making activity and, hence, in depriving him of his profit”. The courts have sought to decipher and apply Blake in a number of cases in recent years and dozens of articles have scrutinised and criticised the original decision and the jurisprudence it has spawned. This monograph on the subject of gain-based relief in contract provides a timely reflection on the subject.