Trigeminocardiac Reflex is a comprehensive tutorial reference to the science, diagnosis, and possible treatment of the trigeminocardiac reflex (TCR) that is usually initiated when the trigeminal nerve is disturbed during intercranial surgery. Since first reported in 1999 by co-Editor Bernhard Schaller, the research focused on TCR is expanding. While its instance is rare, new discoveries are not only increasing diagnosis, but also providing more effective treatment protocols. This text is ideal as a reference for clinical and research neurologists, as a general introduction for clinical presentation, and as a foundation for new research.