[Exploring Mars] includes most current information and thought about the red planet…. [It is] in straightforward, uncomplicated language…. Simpler and less detailed than [Franklyn M.] Branley's "Mars" but more appealing to the average reader. Needs index…. Highly recommended.
Albert Monheit, "Science and Inventions: 'Exploring Mars'," in Junior Libraries, an appendix to Library Journal (reprinted from the October, 1956 issue of Junior Libraries, published by R. R. Bowker Co./A Xerox Corporation; copyright © 1956), Vol. 3, No. 2, October, 1956, p. 25.
[In Exploring the Universe, later published as The Nature of the Universe, Roy A. Gallant looks] at the whole of the universe as we know it, and efficiently relays basic information in a way that captures one's interest immediately.'… The real color and excitement lies in the text. Organized chronologically, it comments on the history of astronomical thought from the days when Egyptians used it for political purposes to the dawn of enlightenment with Copernicus and Galileo. Traditional but apt presentation brings the science up to the present, in which the most advanced and controversial theories are understandably discussed. These, along with profiles of our own planetary system, the stars and the other galaxies, blend to bring on the heady fascination and the more ultimate implications of the subject.
"Non-Fiction: 'Exploring the Universe'," in Virginia Kirkus' Service, Vol. XXIV, No. 21, November 1, 1956, p. 806.