This presentation details the 2005 market shares of leading vendors of application platform software in Western Europe. For the purposes of this study, "application platform" is taken to be the sum of the database management, application server, and integration server functional markets. Each of these functional markets is detailed separately. For each market and for the aggregated application platform, information is provided by operating system and country. Market growth of the leading vendors from 2004 to 2005 is shown at the Western European level. Each detail chart is accompanied by brief notes highlighting the most significant features.