[1X1. Preface[0X The purpose of this package is to allow efficient and flexible input/output operations from [5XGAP[0X. This is achieved by providing bindings to the low-level I/O functions in the C-library. On top of this an implementation of buffered I/O in the [5XGAP[0X language is provided. Further, a framework for serialisation of arbitrary [5XGAP[0X objects is implemented. Finally, an implementation of the client side of the HTTP protocol is included in the package. This package allows to use file based I/O, access to links and file systems, pipes, sockets, and the UDP and TCP/IP protocols. By default the [5XIO[0X package is not automatically loaded by [5XGAP[0X when it is installed. You must load the package with [10XLoadPackage("IO");[0X before its functions become available. Please, send me an e-mail ([7Xmailto:neunhoef@mcs.st-and.ac.uk[0X) if you have any questions, remarks, suggestions, etc. concerning this package. Also, I would like to hear about applications of this package. Max Neunhöffer