If you have a solid grounding in science already, particularly biology, this is probably going to be accessible for you — but if not, you might struggle a little. It starts off alright, but it gets quite dense in places, and if you’re not super-interested, you’ll probably get bogged down. That said, to me it was fascinating, and generated testable hypotheses about how early life could have functioned.
I still disagree with Nick Lane on some points, like the dismissiveness with which he treats “junk” DNA. But he covers a lot of interesting stuff about endosymbiosis, mitochondria, the way mitochondria work with the host cell, how the differences between bacteria and archaea arose… It’s a wide-ranging book, and it’s hard to summarise everything that he touches on.
He also makes some pretty bold predictions about life elsewhere in the universe — that it will work in pretty much the same way as it does on Earth. I don’t disagree with what he says here.
So all in all, a worthwhile read, but bring your thinking cap if you’re not a biologist.