This book offers an accessible, stimulating, and up-to-date introduction to perhaps the most discussed area of physics today. String theory has often been called the aspiring "theory of everything," as the wealth of its elegant structures, which even incorporate quantum gravity, has encouraged its researchers to aim for a unified theory of all known fundamental interactions. However, after decades of research adventures with many achievements but also redefinitions of perspectives, the theory remains essentially unproven as a description of the real world. Does string theory lead to fruitful research directions or is it overrated, as other researchers claim? Perhaps the reader can form their own opinion after reading this book, which combines a clear presentation of the theory with the sincere reflection of one of the pioneering researchers facing the unknown.

After explaining the famous equation E = mc2, the essentials of quantum mechanics, and what we know about black holes, Steven Gubser provides a comprehensive approach to string theory, emphasizing new ideas and their emergence process. By following a presentation that avoids mathematics and uses clever analogies from everyday experience, the reader becomes familiar with strings, branes, string dualities, extra dimensions, quantum fluctuations, and supersymmetry. The final chapters describe the most recent efforts to connect string theory with current high-energy experiments.