So who is the target audience for this type of work? I mean if I want to learn more about something such as combinatorial algorithms, this doesn't seem like it'

So who is the target audience for this type of work? I mean if I want to learn more about something such as combinatorial algorithms, this doesn't seem like it'd be the right place to begin. I want to learn more about the things that I don't know, but at the same time, learning absolutely everything about a single category is typically more depth than I require.