Responsibility to others’ design. Architectural objects often develop over time in cumulative and mutable fashion, through additions and alterations that—perhaps more frequently than not—change the design of a different, original architect (or that of a prior alteration). For any particular changes, or in consideration of design changes overall, we may stipulate obligations to respect original or prior intent and execution. One brand of such obligations, recognized in historic preservation and landmark laws, requires that aesthetic concerns in the public interest trump private interests. Key conceptual questions concern how to determine the source and conditions of any such obligations—and the sorts of responsibilities architects should have to existing structures. Those responsibilities may extend to commitment to the integrity of work by fellow architects.