A great combination of scholarship and educated speculation. The authors approach the formations in multiple ways -- from describing the qualities of the rocks on which the petroglyphs are drawn, to the similarities of technique and composition of groupings across the islands. They provide an in-depth analysis of the grouping at Puuloa, which involved burying of the umbilical stump to insure long life for the newborn child. The comprehensive listing of petroglyph sites on all the Hawaiian islands is invaluable for those of us who would like to search out multiple sites.