From Bernard Most’s website:

The question I am asked most is: “Why did you make so many books about dinosaurs?” Many years ago, when one of our sons, Glenn, was your age, he really loved dinosaurs. I remember coming home from my job as a graphic artist and writer in advertising and reading something Glenn had written in school. He wrote that he “wanted all the dinosaurs to come back to life.” I had been dreaming of writing and illustrating children’s books, and Glenn gave me the idea for the very first book I published, If The Dinosaurs Came Back.