Yesterday's Son Author:A.C. Crispin "Climb aboard the Starship Enterprise as Captain Kirk, Mr. Spock and the rest of their crew travel across space and time in this new adventure. It all begins when scientists, examining prehistoric cave drawings from long-destroyed Sarpeidon, discover a strangely Vulcan-looking figure. Consulted on the puzzle, Spock guesses the truth: The figure ... more »must be that of his own son, fathered when he and McCoy were once transported back in time to ice-age Sarpeidon. His Vulcan sense of duty demands that Spock bring his son into the present - but when he does, in the midst of a Rumulan attack, he finds a young man resentful at his father's coldness and possessing awesome and possibly dangerous abilities."