With the increasing interest in the experimental and clinical application of molecular imaging many institutions create research groups or interdisciplinary centers focussing on the complex development process of this new methodology. The aim for this textbook of molecular imaging is to provide an up to date review of this rapidly growing field and to discuss basic methodological aspects necessary for the interpretation of experimental and clinical results. Emphasis is placed on the interplay of imaging technology and probe development, since the physical properties of the imaging approach need to be closely linked with the biologic application of the probe (i.e. nanoparticles and microbubbles). Various chemical strategies are discussed and related to the biologic applications. Reporter–gene imaging is being addressed not only in experimental protocols, but also first clinical applications are discussed. Finally, strategies of imaging to characterize apoptosis and angiogenesis are described and discussed in the context of possible clinical translation.