The Perugia tunes are new parameter sets for the $ p_{\perp} $-ordered shower and underlying-event model in PYTHIA 6.4, replacing the older "S0" family. These tunes are based on data from LEP, Tevatron, and SPS experiments, including hadronic $ Z^0 $ decays, Drell-Yan data, and min-bias data at various energies. They include a central set called "Perugia 0" and eight variations exploring soft, hard, parton density, and colour structure variations. The tunes aim to predict charged track multiplicities in LHC inelastic, non-diffractive minimum-bias events. They are optimized for matching applications and include lessons from early LHC data. The Perugia 2011 and 2012 tunes are described in appendices. The main features include final-state radiation, initial-state radiation, underlying event, beam remnants, colour reconnections, and energy scaling. The procedure involves manual and automated tuning, with a focus on parameter variations and theoretical uncertainty estimates. The Perugia tunes improve event shapes, fragmentation spectra, and hadron yields, and are tested against data from CDF, DØ, and other experiments. They address issues such as infrared safety, diffraction, and observables sensitive to infrared physics. The tunes are used to model high-$ p_{\perp} $ physics and are compared to data from the Tevatron and LHC. The Perugia tunes are designed to provide a more accurate description of particle production and are used to test the validity of theoretical models in high-energy collisions. The results show good agreement with data, particularly in the high-multiplicity tail, and highlight the importance of considering both infrared-safe and infrared-sensitive observables. The Perugia tunes are an important step in improving the understanding of hadron collisions and are used to guide future experimental and theoretical studies.The Perugia tunes are new parameter sets for the $ p_{\perp} $-ordered shower and underlying-event model in PYTHIA 6.4, replacing the older "S0" family. These tunes are based on data from LEP, Tevatron, and SPS experiments, including hadronic $ Z^0 $ decays, Drell-Yan data, and min-bias data at various energies. They include a central set called "Perugia 0" and eight variations exploring soft, hard, parton density, and colour structure variations. The tunes aim to predict charged track multiplicities in LHC inelastic, non-diffractive minimum-bias events. They are optimized for matching applications and include lessons from early LHC data. The Perugia 2011 and 2012 tunes are described in appendices. The main features include final-state radiation, initial-state radiation, underlying event, beam remnants, colour reconnections, and energy scaling. The procedure involves manual and automated tuning, with a focus on parameter variations and theoretical uncertainty estimates. The Perugia tunes improve event shapes, fragmentation spectra, and hadron yields, and are tested against data from CDF, DØ, and other experiments. They address issues such as infrared safety, diffraction, and observables sensitive to infrared physics. The tunes are used to model high-$ p_{\perp} $ physics and are compared to data from the Tevatron and LHC. The Perugia tunes are designed to provide a more accurate description of particle production and are used to test the validity of theoretical models in high-energy collisions. The results show good agreement with data, particularly in the high-multiplicity tail, and highlight the importance of considering both infrared-safe and infrared-sensitive observables. The Perugia tunes are an important step in improving the understanding of hadron collisions and are used to guide future experimental and theoretical studies.