the first edition appeared in 1917 in a single volume of 793 pages published by cambridge university press. a second edition, enlarged to 1116 pages, was published in two volumes in 1942. thompson wrote in the preface to the 1942 edition that he had written "this book in wartime, and its revision has employed me during another war. it gave me solace and occupation, when service was debarred me by my years. few are left of the friends who helped me write it." the unabridged edition is no longer in print in english, but an edition of 346 pages was abridged by john tyler bonner, and is widely published under the same title. the book, often in the abridged edition, has been reprinted more than 40 times, and has been translated into chinese, french, german, greek, italian, and spanish.