The Collection consists mainly of photographs, newspaper clippings, programs, advertisements, musical scores, trade cards, and broadsides about Crocker's Educated Horses. There are also many souvenir photographs of European sights. There are also two British patents No. 13, 958 in 1887 and No. 23, 307 1899 both related to horse bits. A copy of his published book is not in the Clarke.
Besides a number of articles advertising and critiquing his performance in a number of Crocker’s scrapbooks in the Clarke, there are also a number of article he wrote about the training of horses. He wrote a book, The Education of the horse, illustrated about six years after he came to Europe which was advertised to be published in Scotland and England. Also in the collection of his papers is handwritten musical scores for Crocker’s horses and mules for various instruments including: cornet, trombone, e-flat alto saxophone, bass, and violin. The music notes the barrel act, the handkerchief act, acts by various horses, and entry by mules. Obviously, Crocker was a busy man and successful showman of his era.