I'd read much of A.E. van Vogt's work from early teens on. I'd read "The Empire of the Atom" and "The Wizard of Linn" several times, and "The Mixed Men" once.
I just finished "Transgalactic", which turned out to be a Baen compilation of van Vogt stories that are now in the public domain. It has "Empire", "Wizard", and "The Mixed Men," except pieced together out of the original text of the short stories and novellas published in Astounding in 1946-1950.
The novelized versions of all three books were frustrating. I tossed "The Mixed Men" into the trade pile after the first reading. I bored through the Linn stories more than once, but though the overall story was breathtaking, it just didn't make overall sense.
Presented in the original fragments... amazingly, it's much better. Without the extra cruft van Vogt inserted to bring the collections out to novel length, they make coherent sense, even if they skip around a bit. Same with "The Mixed Men."
There are also two stories about the ezwal, intelligent beings encountered during the war against the Rull. I don't think I've encountered either story before; I'm sure van Vogt did one or more novels including the text, which is what makes van Vogt's stuff so frustrating. At least Lovecraft and Howard's work was prostituted by others; van Vogt cheerfully recycled stuff he'd already sold, which is why when you think you've read something before... you probably have, except it was in an entirely different story.