The two authors, Dr. Nicholas Graziane and Dr. Yan Dong, each have over 10 years of experience in the field of electrophysiology. Dr. Graziane started his research career in 2003 and he continues to perform electrophysiologically relevant research as an assistant professor at Penn State College of Medicine. Dr. Dong had been running an active electro- physiology laboratory and teaching electrophysiology for ~15 years. The partnership of these two authors was specifically designed to provide a student-friendly electrophysiology guide that explains complicated concepts in a straightforward manner. More importantly, the authors address the most common errors that occur during electrophysiological measurements and the most straightforward approaches that can be implemented to correct these errors. In this second edition volume, Drs. Graziane and Dong have teamed up with Dr. Xiyu Zhu and Dr. Anthony Grace in order to provide a comprehensive description of in vivo electrophysiological applications. Dr. Anthony Grace has over 40 years of published experience using in vivo electrophysiology, has published more than 350 articles (H index 111) and is an expert in recording from midbrain dopamine neurons and their relevant corticolimbic structures. Dr. Xiyu Zhu is a trainee in the Dr. Grace laboratory with over 5 years of experience in in vivo recording techniques, whose expertise have been significantly contributing to several research articles. It is the hope of the authors that their efforts will guide and enrich the knowledge of an aspiring electrophysiologist with a passion for neuroscience.