An introduction to the theory of biologial conservation, including a wealth of applications to the fishery and forestry industries. The mathematical modeling of the productive aspects of renewable-resource management is explained, including both economic and biological factors, with much attention paid to the optimal use of resource stocks over time. The Second Edition includes new chapters on the theory of resource regulation and on stochastic resource models, new sections on irreversible investment, game-theoretic models, dynamic programming, and an expanded bibliography.