Regardless of one's perspective, this book is well worth reading, and I would recommend it to anyone interested in philosophy of language, linguistics or the intersection between the two disciplines. If you share Collins' basic assumptions, he provides a cogent defence of how one of the workhorses of syntax, Merge, offers a way into the problem of unity. If you do not share his assumptions, the book challenges alternative approaches in ways that will surely spark lively and fruitful exchanges ... Regardless of your position on these issues, the last chapter is not to be missed: it contains what may well be the best philosophical discussion of Merge and its place in linguistics.