The first involves the book as a physical object – a rectangular brick of paper with, one hopes, a nicely designed jacket. The colourful cover art catches the eye. The intriguing title captures the imagination. The size gives an approximation of its length, and the time it will take to read it.
The second involves the actual reading. Eyes fix on the text and methodically moving down the page, left to right, one line at a time. The book itself all but disappears. Attention is not with the physical object of the book, but with the story being told.