Actually, the recommendation is for all three books in Ian Tregellis’s Milkweed Triptych (Bitter Seeds is merely the first of the three), but the series is not yet in omnibus form. The series is very much alternate history horror (Second World War era), with definite elements of unapologetic cosmic horror. I enjoyed all three books in the series, for given values of ‘enjoyed;’ horrible place to visit, and danged certain that I’d never want to live there, but the locale has its charms. Again, for given values of ‘charmed’ and all that.
Adieu, Quatermass and the Pit: Five Million Years to Earth (BFI Film Classics). Your time will come! Soon. Soon.