After the Last Race is one of three titles written by Koontz in 1974. The other two were Strike Deep by Anthony North and Surrounded by Brian Coffey. All three were published by different houses.
From 1970-1987 Dean Koontz wrote under numerous pen names. Among them the aforementioned North and Coffey, plus KR Dwyer, David Axton, John Hill, Leigh Nichols, Owen West, Richard Paige, Aaron Wolfe, and Deanna Dwyer.
Many of the titles have been reissued under Koontz' own name, however, the true first editions bear the pen names, and as such, are much more collectible.
The true first edition of After the Last Race was published in 1974 by Athenaeum and states "FIRST EDITION" on the copyright page. A collectible copy will bring between $250 and $700. So, nice find!