Developments in the Law Governing Online Activity: The Criminalisation of Catfishing and Civil Relief in Cases of Image-Based Sexual Abuse provides a catalog-style overview of recent legal changes addressing online conduct. The work surveys statutory provisions, regulatory guidance, and judicial decisions that pertain to deceptive online practices and the harms they produce. Emphasis is placed on the criminalisation of catfishing—processes in which individuals misrepresent themselves or conceal true identities in digital interactions—and on the parallel evolution of civil remedies for victims of image-based sexual abuse. The discussion frames these developments within broader questions of accountability for online behavior, the adequacy of existing criminal offences to deter manipulation, and the responsibilities of platforms and other intermediaries in preventing harm. In its treatment of civil relief, the analysis maps remedies available to victims beyond punishment, including damages, injunctions, and protective orders aimed at redressing harm from the non-consensual use or dissemination of intimate images. The work considers applicable legal theories, notably privacy protections and data-protection regimes, alongside tort-based or civil-law avenues that may support claims arising from image-based abuse. Attention is given to practical considerations such as proof of harm, evidentiary challenges, and potential liability for third parties, including platforms, where contributors to the wrongdoing can be identified. Jurisdictional variation and cross-border implications are highlighted as central factors shaping enforceability and remedies in online contexts. Across its sections the work maintains a doctrinal and policy-oriented stance, mapping how evolving rules intersect with enforcement practice, victim protection, and platform accountability. The catalog-style presentation aims to offer a concise reference for researchers, legal practitioners, and policymakers seeking an overview of current trends in criminal and civil responses to deceptive online activity and to image-based sexual abuse.