Massimo Vignelli, mastermind of the iconic New York City subway map, is one of today’s most celebrated graphic designers and a fierce champion of intellectual elegance. My friends at Pentagram have put together this lovely short documentary, which takes us inside Vignelli’s book-design process with equal measures practical insight and witty inspiration:

The grid is an integral part of the book design. It’s not something that you see, physically. It’s just like underwear: You wear it, but it’s not to be exposed. So the grid is the underwear of the book.

Pair with this fantastic, wide-ranging interview with Vignelli.