Who built Avebury and Stonehenge? Why and when were more than 600 stone circles, and thousands of barrows and cairns, erected in prehistoric Britain? What were they used for and what do they tell us about the beliefs and culture of their builders? Riddles in Stone is a history of the extraordinary variety of answers that have been given to these questions, by amateurs and professionals, archaeologists and astronomers, mystics and systems theorists.

While modern excavation and radiocarbon dating has undoubtedly advanced our knowledge of the sequence and date of the monuments,...