Two books: a later printing of The Astonishing Hypothesis: The Scientific Search for the Soul, hardcover with dust jacket, signed on the title page in black ink by Francis Crick; and a later printing of The Survival of the Wisest, hardcover with dust jacket, signed and inscribed on the half-title page in black ink, "For John & David Keppel—I'm sure you will see some resemblances, encouraging & hopeful, Jonas Salk, 9 Oct. 1978." In overall fine condition, with light wear to the Salk dust jacket.
