This exciting and original work emphasizes the importance of William James's interest in health and medicine and shows how it influences many dimensions of his thought that might appear unrelated. The book focuses on James's understanding of himself as seriously unwell and on his shifting conception of good health and how we should aim at it. Sutton shows that James considered himself to be unwell for his whole adult life. He was in constant search of therapies that would improve his physical and his psychological condition. Since James believed that the philosophy we defend is an expression or reflection of our most inner characteristics and temperament, Sutton's thesis that keeping his self-reported ill health in mind will shed light on his thought is eminently plausible.

For a short text, it covers a lot of ground. It starts with James's earliest intellectual development and charts a course that continues to the end of his life. In doing so, Sutton provides a genetic account of his thought that aims to identify significant developments and show how they were influenced by his preoccupations with health and illness.

Chapter 1 provides a vivid account of the young James's concerns over his physical and mental illness and its moral implications. Nineteenth-century discussions of heredity had convinced him that he stood a strong chance of passing on ill health to his children and that such knowledge made it morally unacceptable to reproduce. James's decision to marry and have children, despite strong initial reservations, was only justified by his belief in an unseen metaphysical world. Only on the basis of such a world could otherwise meaningless suffering be meaningful and our striving in the face of suffering have permanent value.

Although I hesitate to accept the strongest formulations of Sutton's claims that these issues were ‘the centre of gravity around which everything else revolved’ (p. 43), this offers an interesting and fertile perspective on James's work. As is well known, James's reading of Charles Renouvier's defence of free will had a huge impact on his philosophical views and mental well-being. Reading Sutton's work, it struck me that one reason he found Renouvier's thought so affecting is that it occurs within a discussion of mental illness. Although Renouvier stresses, as does James, the importance of the passions, he nevertheless argues that a mind unable to resist them through the power of the will would be led to a monomania of ideas. According to Renouvier, mental illness is exhibited through acting according to and affirming ideas with an unreflective will; the will is a necessary condition resisting such action and affirmation, and thus a necessary condition for avoiding such mental illness. Choosing to believe in the will is choosing to believe that we are not all incurably in this state. Since, as Sutton shows, James was haunted by ‘fear of insanity’ (p. 31) at this time, it is no surprise that he was taken by Renouvier's claim that we can, through the will, resist what had seemed to James like a necessary drift towards that unpleasant end. I am sure that Sutton's perspective will help clarify many other aspects of James's philosophical development.

One of the book's theses is that James's understanding of health developed significantly over his life. Chapter 2 discusses James's psychological works of the 1880s and early 1890s. In James's work on habit and his Talks to Teachers, especially, we find a strong focus on how we can mould the physiology of the brain and the body so that they are better adjusted to their environment. Sutton argues that this exhibits the strong influence of Herbert Spencer and his view that perfect health is equivalent to the perfect adjustment of the organism to its environment, where ‘perfect adjustment’ means something like being able to self-preserve with the least amount of difficulty. In Chapter 3, Sutton shows that James became increasingly frustrated with traditional medical ideas about health, and increasingly interested in spiritualism and mind-curists – those who believe that we can alleviate the effects of illness through our mental powers. His study of the latter led him to believe that ‘personal forces effect real change in the world’ (p. 106). This line of thought is expressed explicitly in his 1901–2 lectures, The Varieties of Religious Experience. A few years later, on reading the work of the Italian pragmatist Giovanni Papini, James came to see that these personal forces allow us not only to adjust ourselves to the world but also, more importantly, to adjust our world to ourselves. This inspired James to think of health as our ability to adapt the world to our needs rather than as the Spencerian adaptation of ourselves to the world.

James's thought shifted in significant ways during his life and Sutton's sensitivity to this is one of the book's many merits. However, I have some reservations about this part of the story. Some of the significant changes to James's thinking about health may have occurred earlier than Sutton suggests. Although Spencer was a huge influence, James's first published article from 1878 delivers a devastating attack on Spencer's ideas concerning the organism's correspondence to the environment. Sutton mentions this article in a footnote claiming that James dedicates it to deconstructing ‘the normative content of Spencer's ideas about mental evolution and the environment’ (p. 133 n. 104). However, this underplays the scope of James's attack. James argues that Spencer overemphasizes ‘self-preservation’ as the end of human action. In addition to survival, there are those ends that make self-preservation worthwhile. For James, we do not only try to correspond to the environment, we also want to make the environment one to which it is worth corresponding. Furthermore, although Sutton cites important passages from the Varieties where James stresses the power of human thought to effect change in the world, I think she places the development of these views too late in James's biography. Similar passages can be found in his 1878 article ‘Quelques considérations sur la méthode subjectif’, in which he stresses the transformative power of the belief in a moral universe and that ‘the world will be what we make it’. A plausible alternative hypothesis to Sutton's is that James's sympathy with the mind-curists followed from his belief in the powers of the mind rather than the other way around. Quibbles with this part of the story aside, I agree with Sutton that James's comments on Papini do signify a shift in his thinking. However, I think the shift may be more subtle than the one identified here.

I hope that the concerns raised here about certain details of the story are seen as evidence of the scope for discussion and debate within this work. I have only scratched the surface of the many interesting issues that Sutton presents. As a whole, this book has effected a permanent change on my thinking about James's ideas and given me a new perspective from which to view his work that, from now, I will always try to take into consideration.