This book presents the essentials culminating in the effective string theory of flux tubes in meticulous technical and conceptual detail. The book is divided into four parts. Part One provides historical background, while Part Two (consisting of 14 chapters) covers the passage from Heisenberg's S-matrix theory to String Theory. This includes non-perturbative LSZ formalism, dispersion relations, Regge poles, duality and dual resonance models.

Part Three offers a comprehensive analysis of QCD, focusing on important concepts like asymptotic freedom and quark confinement. The section also delves into lattice gauge theories and effective descriptions of superconductivity and strong interactions. Part Four, the final two chapters, describe the lattice gauge theory determinations of Yang-Mills flux tubes in three and four dimensions and effective string theories, including their systematic constructions. These chapters provide detailed technical information to help readers, especially students, develop their expertise in these ideas.

This book is ideal for graduate students, postdocs, and senior researchers looking to deepen their understanding of effective string theory and related concepts.