I just finished rereading "the sphinx and the megaliths", Now after re-reading it, I remember it had some interesting ideas, not so much on the actual building or quarrying of these very cool structures more on the complex math involve in their design. There are also some interesting idea related to Egyptian solar religion. But a lot of it has to do with the design based on the astronomical considerations. Though for a more strict treatise on the astronomical aspects the books by Alexander Thom (megalithic sites in Britain, megalithic lunar observatories) might be better and Gerald S hawkins (Stonehenge Decoded) book is good.

Irving in this book tries to link the megalithic cultures with the Egyptian culture. An interesting attempt to resolve some of the problems, not impossible. Thee may be more current books.