Presents recent developments and application of fluorescent protein-labelling techniques and two-photon molecular probes. Introduces the theoretical and experimental¿researches of super-resolution localization microscopy, photoacoustic molecular (functional) imaging, and¿optical molecular tomography for small animal in vivo. Illustrates optical labeling techniques and imaging instruments and their application in biological studies. Suits well for researchers and graduates in biomolecular photonics fields.