 Conway and Kosemen began working on the book together after they realized that a vast majority of modern dinosaur artwork did not really portray dinosaurs as real animals, ignoring features such as various type of soft tissue (e.g.skin flaps, pouches, fat) that are unlikely to have survived through fossilization.Both "All Yesterdays" and Conways's, Naish's and Kosemen's later book "Cryptozoologicon" were widely featured in the media.