James E. Allen was a well-established illustrator of stories in popular magazines when, in 1934, he began his association with advertising art. Deane Uptegrove was advertising director for the Alley & Richards advertising agency, who represented the Sinclair Oil Corporation. Uptegrove recommended Allen as an artist for an upcoming dinosaur-centered advertising campaign because he remembered an illustration of a fictional Jurassic sea creature Allen had done for a story in Colliers Magazine a year earlier -- Wetgen, Albert Richard, “At Cinders Lake”, Collier’s, December 30, 1933, p. 22

James E. Allen had four, possibly five, commissions with the Sinclair Oil Company, an association that connected his name with dinosaurs for a generation of Americans.

This booklet was commissioned by the Sinclair Oil Company as a followup to their enormously successful “Sinclair Dinosaur” exhibit at the 1934 Chicago "Century of Progress" World’s Fair, where some 16 million visitors came to see nine full-sized animated dinosaurs.[3][4]

The text was by Dr. Barnum Brown of the American Museum of Natural History. Known as Dr. Bones, he was a popular fossil hunter known for his finding of the first remains of a Tyrannosaurus Rex. James Allen created original oil paintings for the illustrations. Allen worked with Dr. Brown and others at the museum in order to make his depictions as scientifically accurate as possible according to current science[5], sketching first the skeletons before overlaying that with muscle and skin.

The booklet stayed in circulation for years[6], some 650,000 copies in 4 editions. They were given out as a promotion through gas stations (free with purchase), and made available to researchers, libraries, and teachers. Copies are still available today through ebay.

As a promotion in 1935, Sinclair Oil published a dinosaur stamp album and accompanying dinosaur stamps that could only be found at Sinclair service stations. A new set of stamps was issued once per week, available for free "as long as they last, to any boy or girl who asks for them, provided he or she is accompanied by an adult." The response was astounding -- The company noted that “The final totals were 4 million albums and 48 million stamps”. [4]

From inside cover: "A word of appreciation to Dr. Barnum Brown, Curator of Fossils, Reptiles, American Museum of Natural History, New York City -- Sinclair is deeply indebted to Doctor Brown for his careful preparation of the descriptive material in the Sinclair Dinosaur Stamp album and for his help in giving to the boys and gils of America a scientifically accurate account of these fascinating creatures, the Dinosaurs, and some of the contemporary birds and reptiles. The drawings for the Sinclair Dinosaur Stamps were made by James E. Allen under the supervision of Doctor Brown"

The dinosaur stamp promotion was repeated in 1938 (and again in 1959 with new, uncredited illustrations). It contained the same introductory appreciation for the contributions of Dr. Barnum Brown and James E. Allen.