This book has been written during my work in the area of technical communication. The aim was to examine the existing systems used for technical documentation and to build a showcase emphasizing the work with documents in an XML-based environment. Implementing the idea of single sourcing and combining it with the possibilities XML provides, it shows that it is now possible to use the benefits that evolve from these two technologies. All this has been realized in a web application that supports various forms of online XML editing and also provides server-side validation and transformation. This book is aimed at persons in charge at large companies looking for a more efficient way to handle the process of Technical Documentation.