A bit of background: I read this in an avant-garde literature group I am in and the founder of the group is a serious scholar of the Situationists. In fact another group member is a professor of transgressive film and a child of the 60s in NY and SF. So between them they were able to fill me in where the book was lacking. I found it heavy on opinion and short on details, and Home moves very quickly from movement to movement, dismissing nearly everyone along the way. So if, like me, you are a relative n00b to this area of art history, delve deeper.
However, 25 years later, this slender, wisp of a book, with its breezy treatments of several serious art/culture/political groups and movements sprung up after WWII, is *still* the only comprehensive all-in-one work on the topic. Plenty of other authors cover specific people and movements in much greater detail, but if you want a good overview, this is still a good first stop to make. I recommend it as a sort of SI primer.
That said, the book is out of print and not likely to be reissued, although a free PDF is available online (which is how I read it). The "layout" is not very forgiving but, eh, it's a PDF.
I think Home sums up the book pretty well in his afterword:
"Although this text has been an attempt to take an objective view of a dissident tradition, the author has not entirely shed his subjective biases. He has failed to make any proper distinction between an 'ism,' a 'movement,' a 'sensibility' and a 'tradition.' In this Afterword, he will attempt to define these terms. He has chosen not to apply the resulting definitions back onto the main body of the text; preferring to view it as a record of a specific stage in the development of his thought, rather than something which can be definitively completed."
It's worth noting this is Home's first book, written at age 25. The short essays are pretty well written and sourced, but it has a kind of snide, condescending, journaling-at-a-coffeehouse undertone. Blaze through it and pick up Lipstick Traces by Griel Marcus or The Beach Beneath the Street by McKenzie Wark, or others.