Allen - [p.s. not getting mad here ] - I agree there is the occasional rather dense sentence - although I think Lewis' sense of humour comes into play here too: the densest sentence I read in the whole book, I think, was probably exactly the one (first chapter or so) in which he was acknowledging critiques of his work as dense.
However, my sense was that the book was extremely readable, and very jargon-free by the standards of academic monographs (especially in the social sciences) - [i say this as someone who has taught law social sciences at University level for a couple of years a few years back, and has a burning hatred of that over-dense, jargon-filled, basically-inscrutable nonsense!]
Of course, he does use 'technical terms' etc., but I think his defence of this in the opening stages is a good one: that certain terms serve to cue certain understandings in a readership, and not to use these terms would result in a lot more wordiness. Plus, not to use the terms of the discourse would risk locating the book outside that discourse, and that's a risk, especially when one of the functions of the book is to bring greater understanding/study of the AACM!