Bair differs from many of her predecessors in not being a psychiatrist or psychoanalyst. As far as I know she has not undergone a Jungian analysis either; she is a professional biographer and writes about Jung without having adopted a prior position either for or against. While she does not shirk describing Jung's ideas her main focus is on events and personalities. She gives us the fullest account I have seen of his life and relationships. She has had access to a large amount of material, much of it unpublished, and has had many conversations with members of Jung's family and others who knew him, although some of these spoke only on condition of anonymity.
Jung's career went through a number of phases. In his youth he was primarily a scientist, involved in the study of schizophrenia. He carried out pioneer research in word associations, which he used to explore the mental processes of his patients. But a major change occurred when he met Sigmund Freud and became convinced of the importance of psychoanalysis. He seemed destined to become Freud's anointed successor, but theoretical disagreements mounted and culminated in a traumatic break just before the outbreak of the first world war. There followed a period of mental breakdown during which he developed the ideas that formed the basis of his subsequent approach to analysis.
This episode is often given central importance in accounts of Jung's life, but Bair, while not ignoring or downplaying it, treats it more briefly than many others have done. She makes the interesting point that Jung was more productive professionally during these years than has often been implied.
It was during this critical time that he formed his relationship with Toni Wolff, whose support is often credited with preserving his sanity at this time. His wife Emma accepted, albeit reluctantly, Toni's continuing role in her husband's life as "his second wife", and the three remained closely bound up with one another until they died. Toni was much the most important of the women whom Jung was connected with, although by no means the only one.
The middle part of Jung's life was taken up with the development of his method of psychotherapy, which came to be called analytical psychology. He accumulated an ever-growing body of adherents and it became necessary to develop institutions to formalise the situation. Inevitably there followed innumerable power struggles and theoretical disagreements in which Jung was not always impartial.
Jung's later years were increasingly taken up with his studies of esoteric ideas derived from gnosticism, alchemy, and theology. Jung always insisted that he was a scientist not a philosopher, but many people have disagreed with this claim. Toni Wolff, in particular, was strongly opposed to his studies in alchemy and refused to assist him in his research; a decision that led to a considerable cooling in their relations.
Bair presents an excellent and fascinating account of Jung's complex emotional and professional life. None of the other biographies I have read have been anywhere nearly as full in this respect. I was particularly interested to read her account of Jung's correspondence, late in his life, with the Dominican priest and theologian, Father Victor White. Like many of Jung's interactions with men, this one began well, with White's initial enthusiasm for Jung's ideas, followed by increasing questioning that culminated in a complete rupture of relations after the publication of Answer to Job. Jung was always ready to change his views but only when the change came from within himself; he hardly ever countenanced dissent from his followers.
Bair tells us a lot about how Jung's contemporaries reacted to his views, either favourably or otherwise, but she gives little indication of how she herself evaluates them. This is true not only of what she says about analytical psychology but also of how she regards his lifelong interest in the paranormal. I get the impression that she accepts all this pretty much at face value; she even seems to take astrology seriously (as did Jung). I would have welcomed a more open discussion of this.
The book is long and detailed but hardly ever tedious; Jung was too interesting a subject for that and Bair writes well. There are very full notes giving all Bair's sources along with other supplementary material, some of which is interesting, but it's unfortunate that the publishers have made these as difficult to navigate to as possible. The notes are numbered sequentially for each chapter, but they often run into hundreds and it is frustratingly difficult to keep track of where you are. Many books have the courtesy to help the reader by putting "Notes to pages xxx" at the top of each page, but here you must choose either to skip the notes altogether or keep thumbing back and forth.
I should say that anyone who is seriously interested in Jung will want to read this book but it needs to be supplemented by others if you want to get a fuller grasp of his ideas. A good place to start would be On Jung, by Anthony Stevens (1990).