Today Hermann Heinrich Gossen is primarily known to economists as one of the forerunners of the Marginal Revolution. His other contribution to economic theory, namely, a theory of time allocation, is equally if not more significant but not widely cited by economists. Surprisingly this has remained the case despite the availability of several major papers (in English) on his contributions to economic ideas. Building on the work of others, this paper seeks to provide a biographical sketch of Gossen, examine why his work has been neglected, analyze his contribution to economic theory, and assess his influence on the discipline of economics. The paper incorporates discussions on the latest findings about Gossen himself, translations of his book and the implications of his laws for the theory of the evolution of customs.