Papyrus Ebers, dating to about 1500 bce, is the longest surviving medical text from Ancient Egypt. It deals with general medicine and includes diagnoses and cures for over 500 different ailments, as well as sections on physiology and pain management. Sections §854a–855z are now known as the Book of the Heart and have been used by Egyptologists and medical historians alike as the principal source for how the ancient Egyptians thought the cardiovascular system worked and what could go wrong with it. However, most of the ailments described in the Book of the Heart affect the ib which, although very often translated as “heart”, is always associated with mental, emotional and cognitive faculties when it appears outside the medical texts. Unlike previous translations of the Book of the Heart, the one presented here works on the basis that the ib has the same role everywhere it appears, inside or outside the medical texts and when it was not functioning as it should, as described in the Book of the Heart, the emotional and cognitive abilities it represented were outside what was regarded as “normal”, in other words, mental illnesses. When the ailments of the ib are understood in this way it is found that the vocabulary that the Book of the Heart uses is much more appropriate and the translation which is produced is more coherent than previous ones. It also sheds new light on ancient Egyptian ideas about the cardiovascular origins of mental illnesses. This book therefore offers an up-to-date English translation more closely aligned with the original text, and is intended to be used as a source from which those interested in mental illness, whatever their field, can draw their own conclusions. It also contains a summary of the illnesses described and, for Egyptologists, a detailed lexicographical commentary.