With Security in Computing Systems, Joachim Biskup introduces, surveys and assesses the fundamentals of security with respect to all activities that individuals or groups directly or indirectly perform by means of computers and computer networks. He has organized his comprehensive overview on multilateral security into four cross-referencing parts: challenges and basic approaches; fundamentals of information flow and inference control; security mechanisms with an emphasis on control and monitoring on the one hand and on cryptography on the other; and implementations. Besides presenting informal surveys and introductions to these topics, the book carefully elaborates the fundamental ideas by at least partially explaining the required precise formalizations and outlining the achieved mathematical verifications. Moreover, the need to employ the various security enforcement methods in a well-coordinated way is emphasized and thoroughly exemplified, and this includes case studies on UNIX, Oracle/SQL, CORBA, Kerberos, SPKI/SDSI and PGP. Overall, this monograph provides a broad and comprehensive description of computer security threats and countermeasures, ideal for graduate students or researchers in academia and industry who require an introduction to the state of the art in this field. In addition, it can be used as the basis for graduate courses on security issues in computing.