[en] The computer code Zgoubi calculates trajectories of charged particles in magnetic and electric fields. At the origin specially adapted to the definition and adjustment of beam lines and magnetic spectrometers, it has so-evolved that it allows the study of systems including complex sequences of optical elements such as dipoles, quadrupoles, arbitrary multipoles and other magnetic or electric devices, and is able as well to handle periodic structures. Compared to other codes, it presents several peculiarities: (1) a numerical method for integrating the Lorentz equation, based on Taylor series, which optimizes computing time and provides high accuracy and strong symplecticity, (2) spin tracking, using the same numerical method as for the Lorentz equation, (3) calculation of the synchrotron radiation electric field and spectra in arbitrary magnetic fields, from the ray-tracing outcomes, (4) the possibility of using a mesh, which allows ray-tracing from simulated or measured (1-D, 2-D or 3-D) field maps, (5) Monte Carlo procedures: unlimited number of trajectories, in-flight decay, etc. (6) built-in fitting procedure, (7) multiturn tracking in circular accelerators including many features proper to machine parameter calculation and survey, and also the simulation of time-varying power supplies. The initial version of the Code, dedicated to the ray-tracing in magnetic fields, was developed by D. Garreta and J.C. Faivre at CEN-Saclay in the early 1970's. It was perfected for the purpose of studying the four spectrometers (SPES I, II, III, IV) at the Laboratoire National Saturne (CEA-Saclay, France), and SPEG at Ganil (Caen, France). It is now in use in several national and foreign laboratories. This manual is intended only to describe the details of the most recent version of Zogoubi, which is far from being a open-quotes finished productclose quotes