[Power of Three is a] fantasy about events on the Moor after brash Orban kills a Dorig for its golden collar. The delicate balance among the local races—Lyman, Dorig (mound- and water-dwelling fairies), and Giant—is upset when the collar brings a vague but powerful curse down upon all three peoples: the Moor, it seems, will soon be covered with water. Lyman and Dorig blame each other, and all-out war impends until three Lyman youngsters stumble into a friendship with Gerald and Brenda, two Giant children. Enlisting the help of a Dorig prince, the young folk envision a bright new day when their peoples will realize that "we're all the same underneath."… Jones paints lively portraits of her Moor folk and displays an amused humor toward their world, one in which Giants steal children because, as one character says wryly, "they seem to think they can bring them up better"; and the Lymen have an engaging medieval/middle-class approach to their magic. But—horrors!—this isn't MiddleEarth, it's the 1970s. Gerald and Brenda are human kids … and the Moor is being flooded to provide a reservoir for the people of London. The story never recovers from the shock.
A review of "Power of Three," in Kirkus Reviews (copyright © 1977 The Kirkus Service, Inc.), Vol. XLV, No. 15, August 1, 1977, p. 790.