Search for books.
You have to make the rounds. One day a local bookseller will have something you've hoped for for months. Blink and it's gone.
At the SWP bookstore in San Diego I find the first, larger format edition of Reading Capital. My friend finds Essays in Self Criticism in Santa Barbara and I'm envious for years.
I'll drive from San Diego to Berkeley to shop at Cody's and Moe's. Cody's which will later be destroyed by amazon.com.
An inefficient way to match buyers with hard to find merchandise. Now the Internet and FedEx make this easy.
Before the end of our lifetimes, books themselves will no longer be sold. I already have the entire 19th Century on Kindle. It cost about $100 and I carry it everywhere.