Truly personal handheld and wearable technologies should be small and unobtrusive and allow access to information and computing most of the time and in most circumstance. Complimentary, environment-based technologies make artifacts of our surrounding world computationally accessible and facilitate use of everyday environments as a ubiquitous computing interface. The International Symposium on Handheld and Ubiquitous Computing, held for the first time in September 1999, was initiated to investigate links and synergies in these developments, and to relate advances in personal technologies to those in environment-based technologies. The HUC 99 Symposium was organised by the University of Karlsruhe, in particular by the Telecooperation Office (TecO) of the Institute for Telematics, in close collaboration with ZKM Karlsruhe, which generously hosted the event in its truly inspiring Center for Arts and Media Technology. The symposium was supported by the Association of Computing Machinery (ACM) and the German Computer Society (Gesellschaft f r Informatik, GI) and held in cooperation with a number of special interest groups of these scientific societies. HUC 99 attracted a large number of paper submissions, from which the international programme committee selected 23 high-quality contributions for presentation at the symposium and for inclusion in these proceedings. In addition, posters were solicited to provide an outlet for novel ideas and late-breaking results; selected posters are also included with these proceedings. The technical programme was further complemented by four invited keynote addresses, and two panel sessions.