Matt O'Connor, the outfit's founder (and a PR man), says his first pop-up let him launch his brand for a tenth of the normal cost, while testing product ideas.

ECONOMIST: How an alternative trend went mainstream

To launch one of these textbooks you simply go into iBooks like normal, select the title you want with a tap and then wait a few moments.

ENGADGET: Apple iBooks 2 textbook hands-on (video) Hands-on