John S. Daniels is a pseudonym of Wayne. Overholser.

Wayne D. Overholser (born in Pomeroy, Washington) was an American Western writer. Overholser won the 1953 First Spur Award for best novel for Lawman using the pseudonym Lee Leighton. In 1955 he won the 1954 (second) Spur Award for The Violent Land. Three additional pseudonyms were John S. Daniels, Dan J. Stevens and Joseph Wayne; combinations of his three sons' names. - Wikipedia

The author is pictured here (sitting) with his son Steve Overholser (standing) who is also an author.