Leonard Susskind (String Theory)

Leonard Susskind is another founder of string theory. As he recounts in his topic The Cosmic Landscape: String Theory and the Illusion of Intelligent Design, he saw the original dual resonance model equations and thought they looked similar to equations for oscillators, which led him to create the string description — concurrently with Yoichiro Nambu and Holger Nielson. In addition, he has proposed several concepts discussed throughout this topic: string theory of black hole entropy (topic 14), the holographic principle (topic 11), matrix theory (topic 11), and the application of the anthropic principle to the string theory landscape (which is the subject of The Cosmic Landscape; I cover this principle in topic 11).
In addition to his extensive work in string theory, Susskind is well-known for his disagreements with Stephen Hawking over the final fate of information that falls into a black hole, as outlined in his 2008 topic The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics.