The books of the Young People’s Library Series were published in four formats. They are extremely common and except for a few titles (i. e. Alice in Wonderland, Through the Looking Glass) are not very valuable.

These books are frequently dated erroneously because sellers claim the copyright date is the publication date.

Books from this series however are easy to date using a few simple rules. Here is a new dust jacket picture for the database for a format 3 book.
And here is the way to date it.

Each format has a stereotypical design on the spine. The spine shown here-“Format 3 Book”. Format 3 books were published between 1902-1923. See http://henryaltemus.com/ypl/index.htm to see the representative spines.

Now to date the book exactly look at the ads in the back and refer to the dating chart at http://henryaltemus.com/series/series202F3.htm. This book lists 5 Automobile Girls in the ads indicating it is a 1912-1913 book. The uncoated dust jacket and the 1914 inscription solidify the dating based on the ads.