This volume contains the papers presented at the Sixteenth International Conference on Automated Deduction (CADE-16), held in Trento, Italy, July 7{10, 1999, and hosted by Istituto Trentino di Cultura { Centro per la ricerca scientic a e tecnologica (ITC-IRST). The year 1999 marks the 25th anniv- sary of CADE. Since their inception in 1974 at Argonne National Laboratory, the CADE conferences have matured into the major forum for presentation of research in all aspects of automated deduction. CADE-16 was one of the conferences participating in the 1999 Federated LogicConference (FLoC). FLoC'99was the second Federated LogicConference; the r st took place in 1996 and was hosted by DIMACS at Rutgers University, NewBrunswick, NJ.TheintentionoftheFederatedLogicConferences istobring together as a synergetic group several conferences that apply logic to computer science. Theother participatingconferences in FLoC'99were theEleventh Int- national Conference on Computer-Aided Veri cation (CAV'99), the Fourteenth IEEE Symposium on Logic inComputer Science (LICS'99), and the Tenth C- ference on Rewriting Techniques and Applications (RTA-99).Eighty-three papers were submitted to CADE-16: 67 regular papers and 16 system descriptions. Each of the submissions was reviewed by at least four programcommitteemembers, andanelectronicprogramcommitteemeeting was held through the Internet. Of the 83 papers, 21 regular papers and 15 system descriptions were accepted. In addition, this volume contains full papers by two of the four invited speakers, Erich Gr. adel and Robert Nieuwenhuis, along with an abstract of Tobias Nipkow's invited lecture. Zohar Manna gave an invited talk in a plenary session with CAV.
