Introduction and BasicsEngineering of Optimized Fluorescent Proteins: An Overview from a Cyan and FRET Perspective Lindsay Haarbosch, Joachim Goedhart, Mark A. Hink, Laura van Weeren, Daphne S. Bindels, and Theodorus W.J. GadellaFluorescent Imaging Techniques: FRET and Complementary Methods Stefan Terjung and Yury Belyaev Tracking: Sensors for Tracking BiomoleculesProtein-Based Calcium Sensors Thomas Thestrup and Oliver GriesbeckMonitoring Membrane Lipids with Protein Domains Expressed in Living Cells Peter Varnai and Tamas BallaBiosensors of Small GTPase Proteins for Use in Living Cells and Animals Ellen C. O’Shaughnessy, Jason J. Yi, and Klaus M. HahnMolecular Beacon–Type RNA Imaging Felix Hövelmann and Oliver SeitzOptical Probes for Metabolic Signals Yin Pun Hung and Gary YellenGenetically Encoded Voltage Indicators Hiroki Mutoh, Walther Akemann, and Thomas KnöpfelPrototypical Kinase Sensor Design Motifs for In Vitro and In Vivo Imaging Gary C.H. Mo, Ambhighainath Ganesan, and Jin ZhangRNA Samie R. JaffreyFluorescent Sensors for Imaging Zinc Dynamics in Biological Fluids Wen-hong LiHistone Modification Sensors in Living Cells Hiroshi Kimura and Yuko Sato Beyond Live-Cell Tracking: Sensors for Diverse ApplicationsChemical Probes for Fluorescence Imaging in Living Mice Toshiyuki Kowada, Hiroki Maeda, and Kazuya KikuchiOptical Probes for In Vivo Brain Imaging Ksenia V. Kastanenka, Michal Arbel-Ornath, Eloise Hudry, Elena Galea, Hong Xie, and Brian J. BacskaiSmart Imaging Probes for the Study of Protease Function Ehud Segal and Matthew Bogyo Emerging TechniquesSuper-Resolution Imaging Robert K. Neely, Wim Vandenberg, and Peter DedeckerImaging in Optogenetics Xiaobo Wang, Li He, Carol A. Vandenberg, and Denise Montell Index