omnibus of SLAN (1951, solo Van Vogt) + SLAN HUNTER (2007, collaboration: ms. completed by Kevin J. Anderson)

Years ago, Mankind fought against the hated slan race in the fierce Slan Wars. The result was the extermination of almost all slans, and the establishment of a world-wide police state. But slan Jommy Cross had escaped extermination and was now living in constant fear in the world of cruel humans. Jommy was determined to avoid detection, track down other surviving slans, and with them, solve the mystery of the slan's strange existence and superiority...

Slan was serialized in Astounding - September to December 1940. The first book publication was a 1946 hardcover from Arkham House. Revised in 1951 for the Simon and Shuster hardcover - I make the assumption that all reprints use the 1951 revised text (unless you see a statement specifically referring to the Arkham House edition?)