| Author's List |
| title | creator | language | description | tableOfContents | contributor | subject | created |
| The Challenge of the Country A Study of Country Life Opportunity | Fiske, George Walter | en | 2010-06-09 | ||||
| The Challenge of the North | Hendryx, James B. (James Beardsley), 1880-1963 | en | 2006-05-10 | ||||
| Challenge | Untermeyer, Louis, 1885-1977 | en | 2010-09-26 |