This is primarily a series of lenses through which to potentially view trans history, illustrated with examples. The subtitle is less about any one history, and more about how to tackle how to have a history or histories of a group whose identity is very much in flux, and where the current formulations of identity are not always transferable to the past. Their solution is to show all the ways that shaking up gender binaries and gender norms is something that's always happened, and that can and should be part of trans history. The book employs incidents of crossdressing, changing gender while changing societal roles, examples of non-binary gender structures and how all of this interacts with intersex people, to create a kaleidoscope of trans possibilities. Heyam also underlines that we don't have to pick one category or true interpretation of past identities, but rather should look at how many different ways there can be to look at individual lives and choices.

The emphasis is very much on "I'm not saying this meant anyone here was trans in the modern definition, but I am saying this is part of our heritage, and we can't assume that everyone who dressed as a different gender for work (as an example) did not also do it because of gender expression." Heyam wants to challenge the default assumption that everyone in history is cis until proven otherwise, not by assuming they were trans, but by pointing out there's a hell of a lot of grey areas and spaces for ambiguity. It's also a challenge to white supremity and colonialism, and how the patriarchal western European lens on history flattens the possibilities and ignores anything that doesn't fit.

Overall, I found it was convincingly argued, though it did feel like a foundation layer, from which more detailed and advanced arguments could be built up. Any one of the chapters could have been an entire book in its own right, with a lot more examples and analysis. Hopefully, more people will write more books, and we'll get to have that.