Matthew Baillie's treatise on morbid anatomy marks the first systematic textbook on this topic. Approximately 250 years ago, Baillie made detailed descriptions of childhood hydrocephalus in his often forgotten treatise. The present paper reviews this pioneering scientist's life and discusses his original contributions to the description of hydrocephalus in children. It is the early pioneering efforts of such physicians as Matthew Baillie on which our current knowledge base is built. Although hydrocephalus was known in his day, many of Baillie's astute observations on the subject surpassed the efforts of earlier investigators in their level of detail.