You can also order from the publisher . General Optimization Topics H.T. Lau, A Numerical Library in C for Scientists and Engineers . CRC Press, 1995. Handbooks in Operations Research and Management Science, volume 1. A broad reference with large biliography.
Entries are at a fairly advanced level.
H.P. Williams, Model Building in Mathematical Programming , 4th edition. A popular collection of optimization models and modeling techniques. A widely used elementary introduction to optimization topics. Linear Programming D. Bertsimas and J. Tsitsiklis, Introduction to Linear Optimization . Athena Scientific, 1996.