We can think of no other [story] which has such an unusual combination of plot, characterization and vivid sense of place [as does "The Minnow Leads to Treasure" (published in Britain as "Minnow on the Say")]. There is a cleverly detailed challenging puzzle. The alert reader is in constant suspense and eager to unravel the clues with the boys. The study of the two heroes, their families and minor characters is perceptive, and dominating the whole book is the wonderful feeling for the river, with all its twists and turns.

Margaret Sherwood Libby, "Books for Boys and Girls: 'The Minnow Leads to Treasure'," in New York Herald Tribune Book Review (© I.H.T. Corporation; reprinted by permission), March 9, 1958, p. 13.