Biomedical optical imaging is a rapidly emerging research area with widespread fundamental research and clinical applications. This book gives an overview of biomedical optical imaging with contributions from leading international research groups who have pioneered many of these techniques and applications. A unique research field spanning the microscopic to the macroscopic, biomedical optical imaging allows both structural and functional imaging. Techniques such as confocal and multiphoton microscopy provide cellular level resolution imaging in biological systems. The integration of this technology with exogenous chromophores can selectively enhance contrast for molecular targets as well as supply functional information on processes such as nerve transduction. Novel techniques integrate microscopy with state-of-the-art optics technology, and these include spectral imaging, two photon fluorescence correlation, nonlinear nanoscopy; optical coherence tomography techniques allow functional, dynamic, nanoscale, and cross-sectional visualization.Moving to the macroscopic scale, spectroscopic assessment and imaging methods such as fluorescence and light scattering can provide diagnostics of tissue pathology including neoplastic changes. Techniques using light diffusion and photon migration are a means to explore processes which occur deep inside biological tissues and organs. The integration of these techniques with exogenous probes enables molecular specific sensitivity.