Everything in private nuisance turns on the relationship between neighbouring uses of land, and the structure of the tort follows from that. This chapter begins with what private nuisance is, who has standing to sue, who can be made liable, and the remedies a successful claimant can obtain. It then works through the elements of the claim — actionable interference with land, causation and foreseeability — before focusing on the unreasonableness requirement that lies at the heart of most disputes. It closes with the defences, including statutory authority and prescription, the arguments that sound plausible but fail, and how private nuisance differs from the rule in Rylands v Fletcher.