The paper introduces SHOP2, a domain-independent planning system based on Hierarchical Task Network (HTN) planning, which received a distinguished performance award in the 2002 International Planning Competition. SHOP2 generates plans in the same order as they will be executed, reducing reasoning complexity by eliminating uncertainty about the world. It supports partial ordering of tasks and subtasks, incorporates features from PDDL such as quantifiers and conditional effects, and can handle temporal planning domains through a preprocessing technique called Multi-Timeline Preprocessing (MTP). The paper details SHOP2's planning algorithm, domain description features, and optimization techniques. It also discusses SHOP2's performance in the competition, related work, and concludes with a summary of its capabilities and applications.The paper introduces SHOP2, a domain-independent planning system based on Hierarchical Task Network (HTN) planning, which received a distinguished performance award in the 2002 International Planning Competition. SHOP2 generates plans in the same order as they will be executed, reducing reasoning complexity by eliminating uncertainty about the world. It supports partial ordering of tasks and subtasks, incorporates features from PDDL such as quantifiers and conditional effects, and can handle temporal planning domains through a preprocessing technique called Multi-Timeline Preprocessing (MTP). The paper details SHOP2's planning algorithm, domain description features, and optimization techniques. It also discusses SHOP2's performance in the competition, related work, and concludes with a summary of its capabilities and applications.