The ALICE experiment at the CERN Large Hadron Collider (LHC) collected data from fall 2009 to early 2013 using proton and lead-ion beams. The paper describes the running environment, data handling procedures, and the performance of ALICE detectors and analysis methods for various physics observables. ALICE is optimized for studying QCD matter produced in high-energy collisions between lead nuclei. The experiment has a total weight of ~10,000 tons and dimensions of 16 × 16 × 26 m³. It includes central-barrel detectors (ITS, TPC, TRD, TOF, PHOS, EMCal, HMPID), forward detectors (PMD, FMD, V0, T0, ZDC), and the MUON spectrometer. The detectors are designed to handle high particle densities and provide good particle identification capabilities up to 20 GeV/c. ALICE operates at the LHC interaction point IP2, with beam parameters optimized for nuclear collisions. The experiment uses a reduced luminosity in pp interactions and a "main–satellite" bunch collision scheme to manage high beam intensities. The beam parameters, including the beta-star (β*) value, were adjusted to ensure safe operation and to minimize background interactions. The machine-induced background (MIB) was studied, and background rejection techniques were developed using the V0 detector. The background rate was found to be significant in pp running, but the tracking performance was not affected due to the high detector granularity and low transverse momentum threshold. The luminosity determination in pp collisions was performed using van der Meer (vdM) scans, which involved moving the beams across each other in the transverse direction. The cross section for a reference process was measured as a function of beam separation, allowing the determination of the head-on luminosity. The results from these scans were used to measure inelastic cross sections at different energies. The ALICE luminosity determination was compared with other LHC experiments, showing good agreement with ATLAS and CMS results. The data taking involved various running periods, with ALICE collecting data for all collision systems and energies offered by the LHC. The experiment used different trigger configurations, including minimum bias (MB), rare-trigger, and other specialized triggers for specific physics analyses. The trigger system, based on the Central Trigger Processor (CTP), was designed to handle high interaction rates and reduce background events. The data collected included a wide range of physics observables, with the minimum bias data being particularly important for low transverse momentum measurements. The ALICE experiment's performance was evaluated in terms of various physics observables, with a focus on the detection of particles, identification of hadrons, and measurement of jets and muons. The experiment's detectors were calibrated and aligned to ensure accurate measurements, and the data was processed to extract meaningful physics results. The results from ALICE's data taking campaign (The ALICE experiment at the CERN Large Hadron Collider (LHC) collected data from fall 2009 to early 2013 using proton and lead-ion beams. The paper describes the running environment, data handling procedures, and the performance of ALICE detectors and analysis methods for various physics observables. ALICE is optimized for studying QCD matter produced in high-energy collisions between lead nuclei. The experiment has a total weight of ~10,000 tons and dimensions of 16 × 16 × 26 m³. It includes central-barrel detectors (ITS, TPC, TRD, TOF, PHOS, EMCal, HMPID), forward detectors (PMD, FMD, V0, T0, ZDC), and the MUON spectrometer. The detectors are designed to handle high particle densities and provide good particle identification capabilities up to 20 GeV/c. ALICE operates at the LHC interaction point IP2, with beam parameters optimized for nuclear collisions. The experiment uses a reduced luminosity in pp interactions and a "main–satellite" bunch collision scheme to manage high beam intensities. The beam parameters, including the beta-star (β*) value, were adjusted to ensure safe operation and to minimize background interactions. The machine-induced background (MIB) was studied, and background rejection techniques were developed using the V0 detector. The background rate was found to be significant in pp running, but the tracking performance was not affected due to the high detector granularity and low transverse momentum threshold. The luminosity determination in pp collisions was performed using van der Meer (vdM) scans, which involved moving the beams across each other in the transverse direction. The cross section for a reference process was measured as a function of beam separation, allowing the determination of the head-on luminosity. The results from these scans were used to measure inelastic cross sections at different energies. The ALICE luminosity determination was compared with other LHC experiments, showing good agreement with ATLAS and CMS results. The data taking involved various running periods, with ALICE collecting data for all collision systems and energies offered by the LHC. The experiment used different trigger configurations, including minimum bias (MB), rare-trigger, and other specialized triggers for specific physics analyses. The trigger system, based on the Central Trigger Processor (CTP), was designed to handle high interaction rates and reduce background events. The data collected included a wide range of physics observables, with the minimum bias data being particularly important for low transverse momentum measurements. The ALICE experiment's performance was evaluated in terms of various physics observables, with a focus on the detection of particles, identification of hadrons, and measurement of jets and muons. The experiment's detectors were calibrated and aligned to ensure accurate measurements, and the data was processed to extract meaningful physics results. The results from ALICE's data taking campaign (