As one of the oldest parts of English marine insurance law, the foundation of the basic principles of warranty can be traced back to the eighteenth century.1 After 300 years of development, the regime is mature, but also rigid. Since 2006, several consultation or issue papers have been published by the Law Commission in order to change this rigid and unfair regime of warranty law, or to abolish it.2 In order to understand the necessity of reform and the specificity of warranty of legality, this book begins with an introduction of general warranty rules in marine insurance law. This introduction addresses marine insurance law, which relates to general warranty and includes express warranty and implied warranty. This part also introduces warranties in marine insurance law in general, including the origin, classification of warranties, construction rules, and waiver of warranty. Relevant sections in the Marine Insurance Act 1906 are also introduced; however, only the sections that relate to section 41 are considered.