"Darwin and the Mysterious Mr. X" attempts to solve a mystery: "Samuel Butler, a master of acrimonious polemic, confronted Charles Darwin with the sorest of all scientific subjects—a dispute about priority. In "Evolution Old and New" (1879), Butler accused Darwin of slighting the evolutionary speculations of Buffon, Lamarck, and his own grandfather, Erasmus Darwin." The Kirkus Reviews calls it, "... an essay devoted to resurrecting the name and importance of Edward Blyth, a 19th-century naturalist. Eiseley credits Blyth with the development of the idea, and even the coining of the words "natural selection," which Darwin absorbed and enlarged upon ... some thoughts on Darwin's "The Descent of Man"; and a concluding speculation on the meaning of evolution. The last piece is very much Eiseley's poetic from-whence-do-we come/whither-do-we-go vein." Many experts on Darwin such as Stephen Jay Gould disagreed with Eiseley. Michael Ruse, a philosopher of science, even stated "If a work like this was handed into me for a course. I would give it a failing grade." Howard Gruber wrote that "Eiseley was wrong on every count, both in the broad picture he painted of the Darwin‐Blyth relationship and in the minutiae he scratched up to support his claims."