The first edition of the book to bear the title Fundamentals of Physics, first published in 1970, was revised from the original text by Farrell Edwards and John J. Merrill. (Editions for sale outside the USA have the title Principles of Physics.) Walker has been the revising author since 1990. In the more recent editions of the textbook, beginning with the fifth edition, Walker has included "checkpoint" questions. These are conceptual ranking-task questions that help the student before embarking on numerical calculations.