The PYTHIA program is a widely used tool for simulating high-energy collisions, offering a comprehensive set of physics models to describe the evolution from initial hard processes to complex final states. PYTHIA 8.2, the second major release after a complete rewrite from Fortran to C++, has reached a high level of maturity and can now serve as a complete replacement for most applications, particularly for LHC physics studies. The new version includes numerous improvements and bug fixes, enhancing the accuracy and reliability of the simulations. Key features of PYTHIA 8.2 include: - Improved and expanded physics models. - Enhanced parton shower algorithms, including new processes and options for handling mass effects. - Multiparton interactions (MPI) modeling, allowing for multiple hard scattering processes in a single collision. - Beam remnants and color reconnection models to account for complex interactions between partons. - Hadronization based on the Lund string fragmentation framework, with improved handling of junction topologies. The program supports both standalone physics studies and integration with other software packages through interfaces, such as the Les Houches Event Files (LHEF) and the Les Houches Agreement (LHA). PYTHIA 8.2 is designed to handle high-energy collisions between hadrons and leptons, with a focus on hadron-hadron collisions and lepton-lepton collisions. It provides detailed simulations of various cross-sections, including elastic, diffractive, and non-diffractive processes, and allows for the use of different parton distribution functions (PDFs) and matrix element generators. The article provides an overview of the physics models, installation instructions, and key functionalities of PYTHIA 8.2, emphasizing its capabilities and limitations in simulating high-energy collisions.The PYTHIA program is a widely used tool for simulating high-energy collisions, offering a comprehensive set of physics models to describe the evolution from initial hard processes to complex final states. PYTHIA 8.2, the second major release after a complete rewrite from Fortran to C++, has reached a high level of maturity and can now serve as a complete replacement for most applications, particularly for LHC physics studies. The new version includes numerous improvements and bug fixes, enhancing the accuracy and reliability of the simulations. Key features of PYTHIA 8.2 include: - Improved and expanded physics models. - Enhanced parton shower algorithms, including new processes and options for handling mass effects. - Multiparton interactions (MPI) modeling, allowing for multiple hard scattering processes in a single collision. - Beam remnants and color reconnection models to account for complex interactions between partons. - Hadronization based on the Lund string fragmentation framework, with improved handling of junction topologies. The program supports both standalone physics studies and integration with other software packages through interfaces, such as the Les Houches Event Files (LHEF) and the Les Houches Agreement (LHA). PYTHIA 8.2 is designed to handle high-energy collisions between hadrons and leptons, with a focus on hadron-hadron collisions and lepton-lepton collisions. It provides detailed simulations of various cross-sections, including elastic, diffractive, and non-diffractive processes, and allows for the use of different parton distribution functions (PDFs) and matrix element generators. The article provides an overview of the physics models, installation instructions, and key functionalities of PYTHIA 8.2, emphasizing its capabilities and limitations in simulating high-energy collisions.