Notes: - Harper & Row edition published 1950. - Berkley edition / February 1985. - As stated by the author in the new introduction, this edition reprints the 1950 original, not the 1960 revision which was not carried out by Clarke. - The book is illustrated with frontispiece and 15 plates with drawings, photographs and diagrams. The text contains 13 figures and 6 tables. - In addition to the contents below, there are in the end also Mathematical Appendix, Bibliography and Index [pp. 149-164]. - The Note to 1985 Printing is signed ''Arthur C. Clarke / Colombo, September 25, 1984'. - $3.50 in Canada.