On long books

The books that have changed my life are, disproportionately, long. Why?

1. It's about compounding. If there are compounding returns to what a good long book can accomplish, we should expect long books to do a lot more than medium-length ones. (Confirming evidence: my non-book information diet includes a handful of writers I try to read every word from; I think this has a compounding benefit and is, other things equal, advisable.)
2. It's a selection effect. As a book gets longer, it's harder to make the mistake of reading a bad one all the way through.
3. It's a commitment effect. The reader feels more invested.
4. It's a (different kind of) selection effect. Great authors tend to write really long stuff instead of medium-length stuff.
5. It's because we have access to so much good short content. Byrne Hobart points out that air travel made water transport more efficient by letting boats go slower. A better environment for learning from very short things could free up mental resources for very long things (e.g., by removing pressure for those long things to also be a stream of new intellectual stimuli). Tyler Cowen recently pointed out that, for all the talk of short attention spans, people happily sit through very long TV series these days, and it's medium-length material that audiences avoid.
6. It's a(nother different kind of) selection effect. The best content lends itself to expression at great length. Various passages in the sixth volume of My Struggle are among the most intense aesthetic experiences of my reading life; those effects relied on the thousands of pages that came before them.

Andrew Brokos, Kaushik Ghose, and others gave useful feedback on an earlier version of this post.