I have not read all the works in this twice. I have, however, read most of them here and there before finding them in this, a collection of all sorts of works.
Stories -- Time Patrol, alternate world fantasy, far-future adventure, nearer future in-solar-system adventure -- and essays on how to write, and on history, and poetry.
Plus of course, "Uncleftish Beholding," which will test your knowledge of the root words of many words in Atomic Theory.
A couple of them are comic -- including the one I like the least -- but the rest have the touch of Northern hardness he was so good at, even though many have happy endings. (Most? I'm not in the mood to count. 0:) I think the best is "A World Called Maanerek" -- a Dystopian government is experimenting along, and as is common when you experiment, you find results you don't expect. And "A Little Knowledge."
It's a sampler and gives only one of a given type, such as his Time Patrol stories, or the ones that went to make up Operation Chaos. A good sampling.