So, I've been a fan of Baker's work for years (she has a YouTube channel that you should absolutely check out if you're interested in anarchist theory) and I was so excited to finally read her book.
Basically, it's the only book about anarchism that you will ever need to read if you aren't put off by an academic approach. It is extremely well-researched, though this is to be expected of Baker. Her work ethic is unmatched.
She does an incredible job of debunking some of the most annoying myths held by too many non-anarchist leftists (okay, marxists specifically): that anarchism is naive, utopian to a fault, relies entirely on wishful thinking or, most perpexingly, that it has no basis in theory whatsoever. Baker shows us that, in reality, anarchists are and always were pragmatic in their approach. Their beliefs aren't based on some vague hippie kumbaya nonsense, but rather on a specific theoretical framework, that is, a complex theory of practice. Their worldview is informed by a deep knowledge of history, political science and anthropology.
Baker isn't shy to point out when certain practices have failed. She encourages the reader to think critically about historical anarchist movements and to learn from their mistakes. Still, she offers grace to the anarchists of yesterday by considering the larger sociopolitical and historical context they were in.
Although this is an academic book, Baker's dry sense of humor pops in every once in a while which was pleasantly surprising. For example:
What capacities, drives and consciousness people develop varies across social and historical contexts. The capacity to sail a longboat and the drive to die heroically in battle so that you will go to Valhalla developped from living as a warrior in a ninth-century Norse society. These traits are not widespread in modern Nordic societies because people are no longer engaging in that sort of Viking practice. Instead, people engage in practices that develop their capacity to assemble flat-pack furniture or their drive to go to melodic death metal concerts."
That said, if there's one thing I have to complain about, it's that in her desire for clarity and precision, Baker tends to overstate her case. After a certain point, I think I understand what a federation is. I don't need a huge paragraph of her explaining it to me, AND a long quote from a 20th century Spanish guy telling me essentially the same thing but in different words, AND a graphic illustrating the organizational structure of the CNT. Granted this is pretty minor. This book is still more than worth your time, especially if you're a nerdy leftist.