Joe Polchinski (String Theory)

Joe Polchinski proved that string theory required objects of more than one dimension, called branes. Although the concept of branes had previously been introduced, Polchinski explored the nature of D-branes. This work was crucial to the second superstring revolution of 1995. Polchinski’s work is seen as fundamental to the development of M-theory, brane world scenarios, and the holographic principle (all covered in topic 11).
Lately, Polchinski has become a convert to the anthropic principle’s usefulness in string theory, though stories abound of how he once loathed the principle, considering it unscientific and threatening to quit his position if he were forced to adopt it.