Northwest Smith is described on the back cover as a "quick-drawing outlaw of the spaceways", and in her Introduction, C.J. Cherryh describes him as the archetype of Indiana Jones. So you might be expecting planet-hopping tales of action and derring-do.
The NW Smith stories consist mostly of description. Not much happens, but the inaction is luxuriously described. Here's a taste. "...it was truly dreadful. Dimly he knew it, even as his body answered to the root-deep ecstasy, a foul and dreadful wooing from which his very soul shuddered away--and yet in the innermost depths of that soul some grinning traitor shivered with delight. But deeply, behind all this, he knew horror and revulsion and despair beyond telling, while the intimate caresses crawled obscenely in the secret places of his soul--knew that the soul should not be handled--and shook with the perilous pleasure through it all."
It's like that for pages and pages and pages, all nameless horror and soul-shuddering revulsion and despair, until about five pages from the end NW finally pulls his ray-gun and blasts the obscene perilous crawling ancient evil into smithereens.
Most stories have just four characters:
(1) NW himself;
(2) a female story hook, always aluring and exotic, usually alien, always a slave to, or herself the
(3) indescribable and yet comprehensively described nameless ancient horror;
and (4) NW's best friend and partner in crime, who sometimes shows up at the end to help rouse him from the thrall/sleep of the dreadful eons-old soul-sucking obscenity.
Since all that happens in most stories is that NW runs into the alien babe, gets enslaved by the inhuman crawling madness, and eventually either summons the inner strength to draw his ray gun and blast it or gets roused by his best buddy, the stories don't occupy much physical space. Most of them take place in a single town, and most of the action in each story takes place in a single building or even a single room, as NW engages in a soul-deep struggle against the aforementioned nameless indescribable writhing ancient horror.
So if you're expecting fisticuffs, shootouts, dogfights, chases, escapes, rescues, or other forms of Plot, you may want to look elsewhere. In time it takes NW to grapple with, "...knowledge so dreadful that consciously he could not comprehend it, though subconsciously every atom of his mind and soul sickened and writhed futilely away," an Edgar Rice Burroughs protagonist would have found, rescued, and married a princess, killed a few thousand aliens with in swordfights, and been declared a planetary warlord.
But if nigh-endless descriptions of the indescribable are your bag; if you like Poe and Lovecraft but can't stand their breakneck pacing; or if you have a limit of only one weapon discharge per narrative, these stories will be right up your alley. See if you can track down one or two to test-drive before you spring for the whole volume, though.