Distinguishing the earlier from the later editions in this series of ten books can be difficult. The various points are noted at http://henryaltemus.com/series/series132.htm.

A new point of significance has been determined. The very earliest books have a spine title that reads from bottom to top. Here is a brief review on dating these books.

1. The first editions of the first six books only list six books in the ads. These books were published in 1908. Books 7-10 were published in 1909. Here is an example of the earliest advertising pages.

1908 Books

1909 and later

Here is the first edition dust jacket

2. The second printing lists all ten books at 50 cents in both the front ads and on the jacket reverse. The dust jacket is brown and uncoated. (Pre-1915)

3. The third printing is the same as #2 but the dust jacket is white and coated.

4. A variant of this edition has green lettering on the dust jacket reverse.
5. The fourth printing has 50 cent ads in the front of the book but $1.00 ads on the reverse of the dust jacket.

6. The fifth printing of the First Edition lists $1.00 in the front ads and does says “Printed in the United States of America” at the bottom of the copyright/ad page. This indicates a post-1922 publication.

7. The second edition has paste-on pictures on the front cover with new pictorial book appropriate illustrations. On the bottom of the copyright page it says “Printed in the United States of America”. (This indicates a post-1922 printing.) Two formats of this later edition exist. The earlier one has $1.00 as the price listed on the back of the dust jacket. The later book has no price listed.