The main drawbacks of handheld devices (small storage space small size of the displayscreen, discontinuance of the connection to the WLAN, etc.) are often incompatible with the need of querying and browsing information extracted from the enormous amount of data which are accessible through the network. In this application scenario the issues of compression and summarization of data have a leading role: data in a lossy compressed format can be transmitted more efficiently than original ones, and can be effectively stored in the handheld devices (setting the compression ratio accordingly). In this paper we describe a very effective compression technique for datacubes and the architecture of a system (based on this compression technique), called Hand-OLAP which allows a handheld device to extract and browse compressed information coming from an OLAP server distributed on a wired network.