This book presents the lecture course given in 1969 at the Ioffe Physicotechnical Institute in Leningrad (now St Petersburg, Russia) by one of the key figures of twentieth century theoretical physics, Vladimir N. Gribov.

The original motivation, brought up by A. Aronov, was for Gribov to present a course on the theory of complex angular momenta that would be understandable for condensed matter physicists. (Those were the days when condensed matter and particle physicists worked hand in hand, shared thoughts, methods and seminars.) The audience consisted of young bright theorists (though some had little or no experience in this specific field). So, to appreciate the book fully and learn from it, the reader should be familiar with the basics of quantum field theory (relativistic invariance, quantum theory of scattering, Feynman diagrams).

The lecture notes were taken down by A. Anselm, Ya. Azimov, A. Bukhvostov, I. Dyatlov, G. Danilov, E. Levin, G. Frolov, V. Gorshkov, L. Lipatov, E. Malkov, V. Shekhter and I.M. Shmushkevich (then in charge of the Ioffe PTI theory department), and edited by L. Frankfurt. E. Kuraev initiated their publication in the form of two voluminous preprints (in Russian) issued by the Kharkov PTI. This informal publication, known as the ‘Kharkov preprint’, immediately became a rarity.

More than 25 years later the effort of preparing an English version of the course was undertaken by E. Kuraev, B. Shaikhatdenov and V. Bytev. The lectures were then edited by G. Korchemsky and L. Lipatov. The final English translation was carried out by V. von Schlippe; the authors of the following Introduction share responsibility for the final scientific editing.