At first glance this book is a good start off point for queer history (part 1) and terminology (part 2), albeit with it's flaws - the first being that it is lacking a reference/further reading at the end of the book; this is the type of book where one of those is quite essential, in my opinion. Like the word Handbook is in the title.
At first, i saw this as a school book: it gives you the basics, some info isn't exactly right, isn't there and sometimes is even plain wrong, but it's meant to give you the tools to expand on it (which is why it needs those references at the end!)
Positives first: i did learn some bits of history that i didn't know, and i really appreciated that; although flawed, i quite enjoyed the history section. 
However, i feel that the research was really lacking. The fact that the writers are queer is commendable, but, as they state, they didn't know much about queer history/theory/discourse beforehand, and it shows. There were parts where i strongly felt this was written by someone either younger than me or that didn't take part of the queer discourse before like 2015 or so. 
Even more obvious is that they didn't consult many other queer people - the bisexual sections are the most obvious example, being just plain wrong, and i saw significant flaws for a few other identities' terms. 
The visuals are fun and what made me get the book, but the font and font size isn't fun to read, especially at parts where the font colour and background colour clash (this might me an copy thing, because i've noticed the colours on my cover are off). Furthermore, the tone fluctuated so much and the subjective comments didn't mesh seamlessly. And this is only a pet peeve but i cannot read "and so on" one more time.