Say that the universe is a hologram. Say that reality is an illusion projected from lower dimensions. Say that you’re even smarter than Stephen Hawking (at least when it comes to black holes and what dribbles out of them). If you’re Leonard Susskind, father of string theory, then who knows? You might be right. Clear writing and a sprinkling of black-and-white doodles make this upward trudge through Theoretical Physics 101 (and 201) a satisfying haul. But if it’s proof you want, come back next millennium.