This time it’s the Web Service Facade for Legacy Applications. Unlike many of the other patterns and practices, this is very lightweight – a scant 20 pages after you take out the coverage of the included sample application. However, a bigger issue that the lack of content is the definition of “legacy application”. This guide discusses three possible legacy apps – those that expose a COM interface, those that expose a DLL and those in a standalone EXE. However, when my customers talk about legacy apps, they’re usually referring to apps running on the mainframe. A more relevant guide in this vein would talk about using Host Integration Server to provide Web Service Facades for mainframe transaction programs.