This chapter introduces the historic development of life cycle costing (LCC), dating to the 1930s, and the establishment of the method, based in part on the needs of the military. LCC is defined as a precise tool with 3 variants. Conventional LCC, the historic method, is contrasted with environmental LCC, which uses equivalent systems boundaries and the same functional unit as life cycle assessment (LCA) and which comprises a complementary impact assessment. This new environmental LCC is the main focus of this book. Societal LCC, the 3rd variant, includes an expanded scope still under development, monetizing externalities. This approach stands in contrast to conventional and environmental LCC, which account only for real monetary flows borne by 1 or more actors in the life cycle, even though also anticipated monetary flows in the case of environmental LCC. The idealized case of a washing machine offers examples of considerations for each variant, and the case continues throughout the book as a cross-cutting element in each chapter. The introduction is completed by discussing the key limitations of LCC as preexisting, which should be overcome by environmental LCC and by outlining a general framework for environmental LCC beneficial for a future code of practice or standardization.