The role of expert witnesses in medical malpractice litigation is often misunderstood. Much maligned, the expert has been the subject of castigation by a range of people, from his professional colleagues to the jurists who preside over his testimony. From an academic perspective, the expert witness is a necessary evil, and his denigration is his own doing; for the expert is a neutral character who creates his own professional persona. This purpose of this article is to serve as a primer for those interested in understanding the role that the expert is supposed to play in litigation, and the factors surrounding his activities.