Books are
damn good interfaces for reading long-form text. Footnotes, end notes, indices (sure search is handy—indices are better for some things, though, by excluding invalid partial matches and other irrelevancies) glossaries, integrated author bios and expert introductions, and so on. Multi-page marking with near-instant switching. Two pages visible at a time. Cover, title, and author visible when sitting on the table not actively in use, to help passively absorb and retain that info—ever forget who wrote an ebook
while reading it? Spatial recall. Margins to mark on or write notes in. They're
excellent. E-book readers are a replacement only for disposable cotton-candy fiction—which has its place, and that part's nice.
Maybe one day computers and digital readers will actually be good enough to replace books. They're not even close today. The tech's just great.