MAVEN: Modular aspect verification and interference analysis. Aspects are program modules that include descriptions of key events (called join-points) and code segments (called advice) to be executed at those key events when the aspect is bound (woven) to an underlying system. The MAVEN tool verifies the correctness of an aspect relative to its specification, independently of any specific underlying system to which it may be woven, and also allows establishing noninterference among aspects, or detecting potential interference. The specification includes assumptions about properties of the underlying system, and guaranteed properties of any system after the aspect is woven into it. The approach is based on model checking of a state machine constructed using the linear temporal logic (LTL) description of the assumptions, a description of the join-points, and the state machine of the aspect advice. The tableau of the LTL assumption is used in a unique way, as a representative of any underlying system satisfying the assumptions. This is the first technique for once-and-for-all verification of an aspect relative to its specification, thereby increasing the modularity of proofs for systems with aspects. The individual correctness proofs along with proofs of interference freedom are appropriate for a library of reusable aspects, when multiple aspects are to be woven to a system.