A defect or largess, a sensory fusion or transcendental sensing, synesthesia is known for over 200 years and is defined as a cross-modal sensory linkage. Despite of the wealth of literature on synesthesia, this book is one in a kind, as it pioneers in exploring this phenomenon in the courts of law. Based on 134 updated scientific sources, the current effort stratifies synesthesia into the eight clinical groups and reviews the legal and legislative forum around this phenomenon. In an effort to understand the impact of synesthesia on establishing evidence, or defendants' motivations behind the actions plausibly obscured with collided sensations (especially in traffic accidents), the case law is studied. A discussion about reasons, to which we could imply the absence of synesthesia-defense in criminal justice or torts, is provided.