Introduction. References. Papers: The Observational Evidence for Dark Matter. Contributors: J. Einasto, W.K. Ford, A. Kaasik, J.P. Ostriker, P.J.E. Peebles, V.C. Rubin, E. Saar, N. Thonnard, A. Yahil. The Case against Baryons as Dark Matter. Contributors: D.J. Hegyi, K.A. Olive, D.N. Schramm, G. Steigman, M.S. Turner, J. Yang. Light Neutrinos as Dark Matter. Contributors: J.R. Bond, G. Efstathiou, S.S. Gershtein, J. Silk, Ya.B. Zel'dovich. The Case against Light Neutrinos as Dark Matter. Contributors: M. Aaronson, M. Davis, S.M. Faber, C.S. Frenk, J.E. Gunn, D.N.C. Lin, S. Tremaine, S.D.M. White. The Case for Cold Dark Matter. Contributors: G.R. Blumenthal, M. Davis, G. Efstathiou, S.M. Faber, C.S. Frenk, P.J.E. Peebles, J.R. Primack, M.J. Rees, S.D.M. White. The Microwave Background: Theory and Experiment. Contributors: L.F. Abbott, J.R. Bond, G. Efstathiou, G. Epstein, P. Lubin, J. Silk, G. Smoot, J.M. Uson, T. Villela, N. Vittorio, D.T. Wilkinson, M.B. Wise. Axions as Dark Matter. Contributors: L. Abbott, M. Dine, W. Fischler, J. Preskill, P. Sikivie, F. Wilczek, M.B. Wise. Heavy Neutrinos and Supersymmetric Particles as Dark Matter. Contributors: A.D. Dolgov, J. Ellis, J. Faulkner, H. Goldberg, J. Gunn, J.S. Hagelin, P. Hut, B. Lee, I. Lerche, D.V. Nanopoulos, K.A. Olive, H. Quintana, C.L. Sarazin, D.N. Schramm, M. Srednicki, G. Steigman, M.I. Vysotskii, R. Watkins, S. Weinberg, Ya.B. Zel'dovich. Indirect Detection of Cold Dark Matter. Contributors: S.P. Ahlen et al, J. Ellis, R.A. Flores, IMB Collaboration: J. LoSecco et al, Kamioka Collaboration, B. Kuznik, K.A. Olive, W.H. Press, S. Ritz, J. Silk, D.N. Spergel, M. Srednicki. Direct Detection of Cold Dark Matter. Contributors: S.P. Ahlen et al, D.O. Caldwell et al, M. Goodman, K. Griest, P. Sikivie, M. Srednicki, I. Wasserman, E. Witten.