The German psychiatrist Emil Kraepelin (1856-1926) is justly called "the father of modern psychiatry". He was the first to identify schizophrenia and manic-depression, and he pioneered the use of drugs to treat mental illness. He was also joint discoverer of Alzheimer's disease - which he named after his collaborator, Dr Alois Alzheimer. Kraepelin presented these and other discoveries in successive editions of his "Psychiatrie: Ein Lehrbuch" (definitive 8th edition also now available from Thoemmes Press). Much of this gigantic textbook can only be read in the original German; but parts of it were translated into English, and they had a very profound influence on the development of world psychiatry for the rest of the 20th century. "Manic-Depressive Insanity and Paranoia" (1921) was the last section of Kraepelin's great German textbook to be translated into English. Published in 1921, the book showed for the first time that psychotic depression could have alternating forms of mania and severe melancholy. In Kraepelin's view both manic-depression and dementia praecox (or "schizophrenia") were endogenous psychoses, originating in biological disorder; but he distinguished dementia praecox as deteriorating - that is, as having a very poor prognosis for recovery - from his new category of manic-depression, which was non-deteriorating. Kraepelin's classifications of these disorders have persisted into the 21st century, yet the books in which he first explained them to the English-speaking world have become very hard to find. This facsimile reprinting of "Manic-Depressive Insanity and Paranoia" should be of interest to researchers in academic and clinical psychiatry, and to those with a more general interest in the history of medicine.