The book was made at an interesting moment, after the first season of TNG (so Ferengi, Bynars, Betazoids, and Benzites are here, but not later season Next Gen critters like the Borg, Cardassians, or Bajorans), and before the draconian canon policy was instituted by Gene’s attorney, so it was assumed the animated series was canon (it would be re-canonized circa DS9). It also used information from the John M. Ford and Diane Duane novels, including their explanation for forehead/non forehead Klingons. It also calls the Klingon homeworld Kling (...uuuugh) as it was called once, and only once, in the first season TNG episode, “Heart of Glory.”
