This Practice Note introduces the sources of marine insurance law together with key concepts of marine insurance, including insurable interest, warranties, seaworthiness, maritime perils and perils of the sea. It provides guidance on valued and unvalued policies and time or voyage policies and on the institute clauses. It covers policyholders’ obligation to sue and labour, Inchmaree clauses, general average and salvage. It also provides guidance on actual and constructive total losses and on notice of abandonment.