Moreover, scholars view his unorthodox methodology (for example, using comparative mythology to derive scenarios in celestial mechanics) as an unacceptable way to arrive at conclusions. Stephen Jay Gould offered a synopsis of the mainstream response to Velikovsky, writing, "Velikovsky is neither crank nor charlatan—although, to state my opinion and to quote one of my colleagues, he is at least gloriously wrong ... Velikovsky would rebuild the science of celestial mechanics to save the literal accuracy of ancient legends." Velikovsky's bestselling, and as a consequence most criticized, book is "Worlds in Collision". Astronomer Harlow Shapley, along with others such as Cecilia Payne-Gaposchkin, were highly critical of Macmillan's decision to publish the work. The fundamental criticism against this book from the astronomy community was that its celestial mechanics were physically impossible, requiring planetary orbits that do not conform with the laws of conservation of energy and conservation of angular momentum. Velikovsky relates in his book "Stargazers & Gravediggers" how he tried to protect himself from criticism of his celestial mechanics by removing the original appendix on the subject from "Worlds in Collision", hoping that the merit of his ideas would be evaluated on the basis of his comparative mythology and use of literary sources alone. However, this strategy did not protect him: the appendix was an expanded version of the "Cosmos Without Gravitation" monograph, which he had already distributed to Shapley and others in the late 1940s—and they had regarded the physics within it as absurd. By 1974, the controversy surrounding Velikovsky's work had permeated US society to the point where the American Association for the Advancement of Science felt obliged to address the situation, as they had previously done in relation to UFOs, and devoted a scientific session to Velikovsky featuring (among others) Velikovsky himself and Professor Carl Sagan. Sagan gave a critique of Velikovsky's ideas (the book version of Sagan's critique is much longer than that presented in the talk; see below). His criticisms are available in "Scientists Confront Velikovsky" and as a corrected and revised version in the book "". It was not until the 1980s that a very detailed critique of "Worlds in Collision" was made in terms of its use of mythical and literary sources when Bob Forrest published a highly critical examination of them (see below). Earlier in 1974, James Fitton published a brief critique of Velikovsky's interpretation of myth (ignored by Velikovsky and his defenders) whose indictment began: "In at least three important ways Velikovsky's use of mythology is unsound.