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This engaging and beautifully written *book gives an authoritative but accessible account of some of the most exciting and unexpected recent developments in theoretical physics. *

– Professor Lionel J Mason, Mathematical Institute, University of Oxford

String theory is often paraded as a theory of everything, but there are a large number of untold stories in which string theory gives us insight into other areas of physics. Here, Bill Spence does an excellent job of explaining the deep connections between string theory, particle physics, and the novel way of viewing space and time.

**– Professor David Tong, Department of Applied Mathematics and Theoretical Physics, University of Cambridge**

Foremost amongst Nature’s closest-guarded secrets is how to unite Einstein’s theory of gravity with quantum theory – thereby creating a ‘quantum space-time’. This problem has been unsolved now for more than a century, with the standard methods of physics making little headway.

It is clear that much more radical ideas are needed, and our front-line researchers are showing that string theory provides these. This book describes these extraordinary developments, which are helping us to think in entirely new ways about how physical reality may be structured at its deepest level.

Amongst these ideas are that

- Everything can happen at the same time – it is all Now;
- Hidden spaces, large and small, are everywhere amongst us;
- The basic objects are ‘membranes’ that behave like soap bubbles and can explore the shape of spacetime in new ways;
- We are holographic projections from higher dimensions;
- You can take the ‘square root’ of gravity;
- Ideas from the ancient Greeks are resurfacing in a beautiful new form;
- And the very latest work shows that ‘staying positive’ is essential.

The book is aimed at a general audience, using analogies, diagrams, and simple examples throughout. It is intended as a brief tour, enabling the reader to become aware of the main ideas and recent work. A full list of further resources is supplied.

**Bill Spence** is the founding Director of the Centre for Research in String Theory at Queen Mary University of London. He has worked on string theory for over three decades.

1. Introduction

2. Everything is Now - then

3. It’s right behind you

4. My donut has no hole

5. Brane waves, or we’re just blowing bubbles

6. You are a screen idol

7. Let’s twistor again

8. The square root of gravity

9. It’s only Platonic

10. Everything is Now - now

11. Accentuate the positive

12. The future

13. String theory and reality

14. References and further resources

### Biography

Bill Spence is Professor of Theoretical Physics and founder of the Centre for Research in String Theory at Queen Mary University of London.

`This engaging and beautifully written book gives an authoritative but accessible account of some of the most exciting and unexpected recent developments in theoretical physics.'

Professor Lionel J Mason, Mathematical Institute, University of Oxford

'String theory is often paraded as a theory of everything, but there are a large number of untold stories in which string theory gives us insight into other areas of physics. Here, Bill Spence does an excellent job of explaining the deep connections between string theory, particle physics, and the novel way of viewing space and time.'

Professor David Tong, Department of Applied Mathematics and Theoretical Physics, University of Cambridge'This unusual book provides a concise description of some of the most exciting developments in theories of fundamental particles and their forces that have emerged from the study of string theory. The underlying ideas involve a mix of subtle physical insights and sophisticated mathematics, which are difficult to convey to a non- specialist audience, However, in eleven short chapters Bill Spence manages to describe the essence of the subject with great clarity.

The subject of String Theory evolved from the assumption that the many different fundamental sub-atomic particles are identified with different kinds of vibration of an extended string-like object. It subsequently developed into a much broader subject that provides a mathematical framework for unifying the fundamental particles with the quantum geometry of space and time through which the particles move.

A striking feature of many developments in this area over the past forty years is the remarkable symbiosis of theoretical physics with modern mathematics. Not only has new mathematics transformed the understanding of string theory and quantum field theory but the developments in these areas of theoretical physics have fed into some of the most important developments in mathematics. This book succeeds remarkably well in conveying these key developments and, rather amazingly for a subject that is so closely connected to mathematics, it contains virtually no equations!

The book’s main themes include seemingly esoteric subjects such as topological features of extra dimensions of space, the geometry of twistors, mirror symmetry and the "holographic" unification of general relativity (Einstein’s theory of gravity) with theories of the other forces. All these are described in a manner that avoids hyperbole and over-simplification while avoiding all mathematical detail..

This short book will appeal to intelligent non-experts with no mathematical background who would like a brief overview of the field. It also provides a stimulating introduction for young people thinking of pursuing fundamental areas of physics or mathematics in more depth.'

Professor Michael B Green FRS, Professor of Theoretical Physics, University of Cambridge/Queen Mary University of London. Pioneer of String Theory research