here. Each of us can probably name a dozen titles that we think should be included in such a venture. I do not include anything by either Poul Anderson or James Blish simply because I think that the entire works of both authors should be kept permanently in print. Wells is not included because he is in print. Here are six:
Lest Darkness Fall by L. Sprague de Camp
Bring The Jubilee by Ward Moore
The Technicolor Time Machine by Harry Harrison
The Anubis Gates by Tim Powers
Gladiator by Philip Wylie
The Black Cloud by Fred Hoyle
De Camp and Moore are precursors of Anderson's Time Patrol (see here). The Technicolor Time Machine and The Anubis Gates are circular causality paradox narratives like Anderson's three non-series time travel novels. Gladiator has something in common with one of those three. Which and what?
Wells introduced interplanetary invasion in The War Of The Worlds. Anderson followed this with The War Of Two Worlds. Both had Martians invading Earth whereas Hoyle has an intelligent gas cloud entering the Solar System. Awesome.