This issue of Neuroimaging Clinics addresses the current clinical state-of-the-art in functional brain magnetic resonance imaging. Although other “functional” imaging modalities such as MR spectroscopy and MR perfusion imaging have been deliberately omitted in favor of an emphasis on blood-oxygen level-dependent (BOLD) fMRI and diffusion tensor imaging (DTI), this is largely due to the ever-increasing breadth and depth of current clinical applications of the latter. Functional imaging has arguably changed the standard of care for patients undergoing surgical resection of brain tumors, epileptogenic tissue, and other structural brain lesions. In addition, BOLD fMRI and DTI have been useful for increasing our scientific understanding of different functional networks in the brain and how such networks and their connectivity may be disrupted in disease states. This issue explores applications of BOLD and DTI to presurgical and other pretherapeutic planning and includes articles with focus on the motor, language, memory, and visual systems, often in the context of pretherapeutic planning or specific diseases or patient populations. In particular, applications to epilepsy and pediatric neuroimaging are included, as well as both technical and practical aspects of clinical use of these imaging methods. In addition to conventional task-based BOLD imaging, resting state BOLD imaging is also discussed. Last, economic/business issues relating to the actual running of a clinical BOLD fMRI service are considered, with description of current procedural terminology codes used for billing. Many high-quality color illustrations are included throughout this issue to display important eloquent cortex and white matter tracts in the brain, and an extensive list of references is included for each article in this issue. I hope that this compendium of clinically relevant articles will serve as a broad overview of different functional imaging techniques and applications that will prove to be useful to neuroradiologists, neurologists, and neurosurgeons as well as those who are in training in these respective fields.