People have undergone many forms of visual torture over the years to read on the go. iPhone eReaders are one of the latest, but by historical standards, not as brutal on the eyes as you might think.
Here’s a 1620 edition of the works of Silius Italicus, a Roman poet. (A piquant aside: It may have belonged to a the Bishop of Metz, a bastard son of kind Henry IV, as I mention here.) This is dense reading. An entire epic poem in less volume than a deck of cards. I’m content just to admire the binding.
Silius Italicus, On the Second Punic War, 1620 Dutch edition