Recent developments in the theoretical and experimental analysis of many-particle production are discussed. After a summary of the main characteristics of the high energy reactions, we discuss the features of the multiperipheral model as an introduction to the recent theoretical developments. The longitudinal kinematics and some of their manifestations in the behaviour of cross-sections are reviewed before turning to the concepts of scaling and limiting fragmentation. The implications of these approaches are compared with available experimental data. This leads to the Reggeistic picture developed in Mueller's analysis. Its results are reviewed and analyzed in the regions of limiting fragmentation and pionization. Separate sections are then devoted to the triple-Regge limit and to diffraction dissociation. We close with a section on correlations, pointing out open problems for future research.