th This volume contains the proceedings of the 10 ISAAC conference (Tenth - nual International Symposium on Algorithms And Computation) held in Ch- nai, India. This year's conference attracted 71 submissions from as many as 17 di erent countries. Each submission was reviewed by at least three independent referees. After a week-long e-mail discussion, the program committee agreed to include 40 papers in the conference program. The high acceptance rate is clearly an indication of the quality of the papers received. We thank the program c- mittee members and the reviewers for their sincere e orts. We were fortunate to have three invited speakers this year, providing for a very attractive program: Kurt Mehlhorn (MPI, Saarbruck .. en, Germany), Eva T- dos (Cornell University, U.S.A.), and Kokichi Sugihara (Univ. of Tokyo, Japan). Moreover, the conference was preceded by a tutorial on a cutting-edge area, Web Algorithmics by Monika Henzinger (Compaq Systems Research Center, Palo Alto, U.S.A.) as a joint event with FST&TCS 99 (Foundations of Software Te- nology and Theoretical Computer Science, December 13-15, 1999, Chennai).Asa post conference event, a two-day workshop on Approximate Algorithms by R. Ravi (CMU, U.S.A.) and Naveen Garg (IIT, Delhi) was organized. We thank all the in- ted speakers and special event speakers for agreeing to participate in ISAAC'99.