When I did tackle Charles Harness' The Paradox Men, I loved it. Williamson's Dome I reread once, but it wasn't his best work by a long shot. Paradox Men, on the other hand...
I re-read Paradox this evening, and know enough physics and physiology now to have to force a lot of suspension of disbelief, but the liberties taken aren't for scenery--they drive the plot, which is fast and neatly concluded and as enjoyable as I remembered. Who, and what, is Alar? BTW, the later slightly edited edition is cleaner than the version I remember from 40+ years ago.
Other people have done similar things since (and Frank Herbert borrowed his shields for Dune), but it's a nice un-ironic read.
So if you're willing to forget real physics and physiology for a spell, read it.