Kin is a book about microbes and how they’re related to us, and the surprisingly close ties between microbes and humans. It does a lot of digging into the origin of life in general, really; I didn’t find it as interesting as Nick Lane’s The Vital Question, and ultimately I was also surprised by how bad some of the editing was — it was just careless, typos and missing words, etc.
If you’re looking for a book about where life came from, I probably recommend Nick Lane’s book; I’ll have to have a think for some others which present alternative ideas. Ingraham’s book is easy enough to read, but it didn’t feel quite worth the time for me. Bearing in mind, of course, that I’m finishing up my biology degree at the moment with a dissertation on one particular microbe, so I guess I’m not really the target audience here.