Oh, he left out a bunch of other considerations. My decision tree includes: Is the text graphic-heavy (charts, tables, maps, illustrations) – if so, hard copy. Is the book part of a series of which I already own some volumes in hard copy – if so, probably hard copy; Am I likely to read the book (either first time through or later as reference) dipping in-and-out or cross-referring by flipping through the volume, or is it a book that I'll read front-to-back or in the future look for text by index or keyword search. If the latter, e-book. Is the book available in trade paperback (my heavily preferred hard-copy format) and if so, what's the pricing differential. That's not a sharp decision-point, just an element to go into the mix. If the over-sized Kindle they're supposedly bringing out this week can handle graphics displays better, my buying patterns might shift when I eventually upgrade to a later-version Kindle. Anyhow, what this exercise shows is why I'd hate to be an amazon manager who has to figure out pricing points and then negotiate the deals with each individual publisher, who probably have their own idiosyncratic views as to how to position their products to avoid cannibalization and maximize revenue.