Thinning a Library
“The exercise,” he wrote, “has confirmed concretely what had hitherto been an abstract conviction: it’s a rare monograph that’s actually worth a book. You can digest the idea, pick out a few key pieces of evidence, decide whether or not it really changes your mind about an overall interpretation, and then you’re really, sadly, done with it. Scarcely ever will you revisit it — scarcely ever will it repay you to revisit it, except to check a citation maybe — unlike a good essay or synthesis, which you can always come back to for insights.”
The "good essay" point does seem to say something for the much-maligned critical anthology, however.