This paper describes an approach for verifying programs in the presence of data

abstraction and information hiding,which are key features of modern program

ming languages with objects and modules.The paper focuses on the property o

modular soundness,that is,the property that the separate verifications of the indi

vidual modules of the program suffice to ensure the correctness of the composite

program.The paper introduces a new specification language construct,the ab

straction dependency,and argues that i s needed to achieve modular soundness

in the presence of data abstraction and information hiding.This paper discusses

in detail two varieties of abstraction dependencies:static and dynamic.The pape

also presents a new technical definition of modular soundness as a monotonicity

property of verifiability with respect to scope and uses this technical definition

to formally prove the modular soundness of a programming discipline for static

dependencies.-This paper describes an approach for verifying programs in the presence of data abstraction and information hiding, which are key features of modern program ming languages with objects and modules.The paper focuses on the property o modular soundness, that is, the property that the separate verifications of the indi vidual modules of the program suffice to ensure the correctness of the composite program.The paper introduces a new specification language construct, the ab straction dependency, and argues that it is needed to achieve modular soundness in the presence of data abstraction and information hiding.This paper discusses in detail two varieties of abstraction dependencies: static and dynamic.The pape also presents a new technical definition of modular soundness as a monotonicity property of verifiability with respect to scope and uses this technical definition to formally prove the modular soundness of a programming discipline for static dependencies.