Prepared by the Seismic Retrofit of Existing Buildings Standards Committee of the Codes and Standards Activities Division of the Structural Engineering Institute of ASCE Seismic Evaluation and Retrofit of Existing Buildings, Standard ASCE/SEI 41-17, describes deficiency-based and systematic procedures that use performance-based principles to evaluate and retrofit existing buildings to withstand the effects of earthquakes. The standard presents a three-tiered process for seismic evaluation according to a range of building performance levels by connecting targeted structural performance and the performance of nonstructural components with seismic hazard levels. The deficiency-based procedures allow evaluation and retrofit efforts to focus on specific potential deficiencies deemed to be of concern for a specified set of building types and heights. The systematic procedure, applicable to any building, sets forth a methodology to evaluate the entire building in a rigorous manner. This standard establishes analysis procedures and acceptance criteria, and specifies requirements for foundations and geologic site hazards; components made of steel, concrete, masonry, wood, and cold-formed steel; architectural, mechanical, and electrical components and systems; and seismic isolation and energy dissipation systems. Checklists are provided for a variety of building types and seismicity levels in support of the Tier 1 screening process. This new edition, which updates and replaces previous editions of ASCE 41, introduces revisions to the basic performance objectives for existing buildings and to the evaluation of force-controlled actions. It revises the nonlinear dynamic procedure and changes provisions for steel and concrete columns, as well provisions as for unreinforced masonry. Standard ASCE/SEI 41-17 is a primary reference for structural engineers addressing the seismic resilience of existing buildings and for building code officials reviewing such work; it also will be of interest to architects, construction managers, academic researchers, and building owners.