This fascinating book contains a re-evaluation of stone circles, introducing readers to little known circles and bringing new insights about some of the better known ones. When John R. Hoyle became aware of Professor Alexander Thom's work on stone circles, he set out to examine other rings and sites in mid-Wales to see if they conformed to Thom's theories. Hoyle studied several lesser-known rings, one alignment and examined other remains having properties similar to those ascribed by Thom to lunar and solar observatories. The author's analysis not only reveals important differences in the measurements used within different groups of stone circles - important because can indicate changes in beliefs - but also discusses flattened stone circles, distances to outliers, properties of sightlines and suggests an explanation for cup and ring marks. Hoyle also offers up an alternative to the design of the Great Ring at Avebury, the probable geometry of a rediscovered ring and looks at the geometrical and mathematical knowledge that the Neolithic people would have used when creating their rings. Megalithic Matters is a fascinating read for anyone interested in stone circles, archaeology and related matters.