## Grand Unified Theory

*Plus*is a special, marking the occasion of Stephen Hawking's 60th birthday. Plus attended his Birthday Conference in Cambridge, where we interviewed some of the world's most influential mathematicians and physicists.

*Plus*talks to

**Sir Roger Penrose**about all this and more.

**Professor Gerardus 't Hooft**has always been fascinated by the mathematical mysteries of nature. He tells

*Plus*about his early life, and what our Universe might really be like.