The first of my blogs on Jung is now up at the Guardian's Cif belief. A taster:

He first made a name for himself in the Burghölzli psychiatric hospital in Zürich, working with Eugen Bleuler, the doctor who coined the word "schizophrenia". Jung developed the word association test of Francis Galton, the cousin of Charles Darwin.

A patient was read a list of words and asked to respond to each one with the first word that comes into their mind. The response, and the time taken to produce it, is recorded.

Previous research had already demonstrated that prolonged response times indicate that the stimulus word unconsciously troubles the patient. Sometimes, it is possible to identify a group of such words. Jung's contribution was to link these groups with the unconscious part-personalities and show how the test provides a window into the distressed world of the mentally ill. People are not simply mad, he concluded. Rather, there is a method in their madness. In one case, Jung showed that a patient who for 50 years had been fixated on the apparently meaningless task of making illusory shoes, had been abandoned by a lover who was a cobbler.