With the rapid development in wireless-network and portable computing and communication devices, mobile users are expected to have access to information from anywhere at anytime in the near future, in the form of ubiquitous c- puting, a term coined by the late Mark Weiser of Xerox, PARC. Indeed, the emerging mobile technology will probably bring us the next wave of information revolution and change our society as we move into the next millennium. Before this vision can be realized, a number of challenges have to be overcome. Tra- tionally, network-based information systems have been developed under wired assumptions about the connectivity and topology of the underlying networks. To eliminate these limitations from wireless and mobile environments, research e orts are needed in networks, architecture, software infrastructure, and app- cation levels, in order to provide mobile data access over hybrid wireless and wired networks, which is the central theme of this conference. Theseproceedingscollectthetechnicalpapersselectedforpresentationatthe First International Conference on Mobile Data Access (MDA'99), held in Hong Kong, followingits returnto China, on December 16{17,1999.Theconferenceis heldin conjunctionwith the InternationalComputer Science Conference, the - ternational Conference on Real-time Computing Systems and Applications, and the Paci c Rim International Symposium on Dependable Computing, forming part of the International Computer Congress.