The general contractor's office sits quiet on a Thursday evening, the day's crew long since dispersed to their homes across the city. At the drafting table, surrounded by rolled blueprints and specification binders from projects spanning two decades, the contractor reviews the legal documents delivered that afternoon by registered mail. The statement of claim names his company as the defendant in an action brought by a non-profit community services agency, alleging that renovation work completed years earlier has resulted in structural deficiencies, water infiltration, and consequential damages to programming operations. The claimed amount runs into hundreds of thousands of dollars. The contractor reads the allegations carefully, his memory reaching back to the project itself, to the challenges of working on an aging building, to the concerns he raised during construction about drainage issues that predated his involvement, to the subcontractor whose foundation work he had questioned at the time. He remembers, too, the conversations with the agency's representatives during the project, their eagerness to complete the renovation quickly to satisfy their government funder, their decisions to defer certain recommendations he had made. As he considers how to respond to this lawsuit, he realizes that his defence will need to go far beyond simply denying that deficiencies exist or that his work caused them. His response will need to raise matters that, even if the plaintiff proves some breach on his part, will shift responsibility, reduce his exposure, or potentially eliminate his liability altogether. This is the domain of affirmative defences, and understanding them is essential for any defendant facing civil litigation in Alberta.