Information is one of the most important assets for businesses. Without it only a few processes are able to perform as intended. The sharing of information with other organizations, which enables quick and automated processing, increases that importance. For information technology (IT), information is the core of its existence. Anything that threatens information or the processing thereof, will directly endanger the results of the organization. Whether it concerns the accuracy or timeliness of the information, the availability of processing functions or confidentially, threats that form risks have to be encountered by security. The text provides a foundation for the management of the IT infrastructure and builds on that basis. The Text also explores how to organize and maintain the management of security of the IT infrastructure, from the IT manager's point of view.