The Escape of Sigmund Freud, By David Cohen

This is a tantalising exploration of Sigmund Freud's dramatic escape from Vienna to London in June 1938. David Cohen's structure has the feel of a free-association analysis rather than the thriller promised by the title. But his writing is passionate, sometimes wry, and always gripping.

Sleuthing into new territories around Freud's life, such as his mysterious Nazi ally Anton Sauerwald, Cohen also unearths Freud family secrets. He discovers the fraudsters, the suicides, the mysterious deaths, the hidden Swiss bank accounts. And, probing Freud's own psyche, he refutes the received perception that Freud divorced himself from his Jewish heritage.

Cohen stresses the importance of Moses as a presence haunting Freud's inner life. Freud's most troubling work, Moses and Monotheism, posits the idea that Moses was an Egyptian who invented Judaism. He only dared publish it once he got to England.

Provocatively, Freud demoted Abraham as the father of monotheism. He believed that the creation of the Jewish God was a development of the concept of the Pharaoh Akhenaten, and that Moses transferred Egyptian belief into a new religion: Judaism. Freud's obsession with Moses, Cohen believes, is because he saw himself as a new Moses developing a new (Jewish?) religion: psychoanalysis.

The book's style is so engaging because Cohen shows Freud interacting with quirky individuals who leap off the page. We get Freud as seen by Hilda Doolittle, Princess Marie Bonaparte, Carl Gustav Jung and Wilhelm Reich.

The central mystery – why Sauerwald went out of his way to help Freud – is never resolved. Cohen realises that too many secrets are still concealed. The Library of Congress houses a huge correspondence between Freud, his patients, friends and family, as well as clinical notes. These are closed until 2020 or 2050, while eight are to be hidden "in perpetuity". What can be so important about Freud's life that it is denied to the public gaze?