Very good, as far as celebrity autobiographies go- informative in sketching the outlines of Numan's career, and it gives a strong sense of him as a person.
The book has a year-on-year format, and Numan naturally focuses on the things that he remembers and cares about most, which means that, sometimes, he gives more space in a chapter to discussing his love of flying (and later boating), or his frustrating, painful (but ultimately rewarding) attempts to have a child with his wife Gemma, or to how his Asperger's has affected his life and career, than he does to his recording or touring activity; and his original commercial peak (1979-81) is over by a third of the way into the book, with quite a bit of space dedicated to the decade-plus creative/commercial wasteland he found himself in afterwards.
Numan is blunt and honest. He's frank about how he feels and felt. This includes times he felt slighted or let down (by his record labels, by other musicians, by himself), which might come across as petty in a book like this, but he's never really angry or vindictive about it- just honestly explaining how he felt, and he's equally quick to praise those who have been kind or helpful to him. He's similarly frank about the mistakes and poor decisions he made that led to various career setbacks, with the benefit of hindsight. He's also willing to be openly frustrated with, or even critical of, people he likes and cares for, including family and close collaborators- again, without any real malice, just a forthright honesty.
This is perhaps not entirely what casual fans of Numan's most popular music would want, but it does give a pretty well-rounded picture of Gary Numan the person. It's clear what he's passionate about (music, his family, planes), and also, by omission, what he's not very interested in (he's only really interested in religion as a theme that might be explored in his art, and he's evidently disinterested in politics, though he exhibits strong feelings about global warming and COVID in particular). Pretty good.