Surface plasmon resonance (SPR) has evolved into an exciting technique in biomolecular interaction analysis. The development of commercial SPR instruments has made the te- nique available to a wide scienti?c audience, and the number of publications in which the use of SPR is described is rapidly increasing. SPR is in use for many purposes from food quality control to the study of nanoparticles. Much research is now focused on devel- ing new SPR-related applications, e.g., SPR imaging, SPR arrays, SPR ?uorescence, and combinations of SPR with mass spectrometry and with electrochemistry. Biomolecular interaction analysis is at the core of many research projects. In principle, the setup of an SPR experiment is simple: There is a sensor surface to which one of the interacting partners (the ligand) is immobilized; the other partner (the analyte) is added in a ?ow or cell-like compartment. The binding phenomenon is monitored in real time as a change in SPR angle. An important issue is the choice of surface and the immobilization strategy. With SPR, it is possible to mimic the biological environment which is relevant for an interaction. For interactions in a water environment, sensor surfaces with hydrogels are available. Many biomolecular interactions take place in a membrane environment. For this, commercial sensor surfaces are available, or surfaces can be tailor-made. This volume contains several examples of building up of lipophilic surfaces. Nature abundantly makes use of multivalent interactions; multivalency can be mimicked on a sensor surface with immobilized ligands. While commercial instruments have expanded the usage and the related literature has increased, the quality of surface plasmon resonance (SPR) research has been hindered by a lack of knowledge of the processes that influence the SPR signal. In Surface Plasmon Resonance: Methods and Protocols , experts in the field present a wide variety of applications involving commercially available SPR instruments. The heart of the SPR technique is to construct a dedicated surface for an assay. Protocols describe such surfaces for many needs, including the study of membrane bound proteins. Beyond the protocols-based chapters, the volume also highlights the backgrounds of vital issues in the use of SPR, including processes occurring within the hydrogel environment of sensors and on lipid membrane surfaces as well as the analysis of kinetic information. Written in the highly successful Methods in Molecular Biology ™ series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible protocols, and notes on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Surface Plasmon Resonance: Methods and Protocols fills a need for well-described, hands-on SPR experimental protocols and promises to inspire the adaptation of these techniques to fit the needs of labs around the world.