"Porno" by Irvine Welsh is a darkly comedic sequel to "Trainspotting," revisiting the lives of Mark Renton, Sick Boy, Spud, and Begbie ten years after their tumultuous escapades. Set against the backdrop of Edinburgh's seedy underbelly, the novel follows their foray into the world of adult entertainment. With Welsh's trademark wit and gritty realism, "Porno" explores themes of addiction, ambition, and redemption.