 The remaining pieces were first published in the present work.The book collects the author's nine tales of time-traveling hunter Reginald Rivers, the hero of his 1956 classic, "A Gun for Dinosaur".He wrote another Rivers story in 1990 to fulfil a request by Robert Silverberg for a dinosaur story for his 1991 anthology "The Ultimate Dinosaur"; afterwards, de Camp added to the sequence until he had enough stories for a book.