Evidential-reasoning methods, such as the Dempster-Shafer calculus of evidence, are widely applied to information fusion problems. In this paper we examine methodological requirements as well as conceptual issues that are relevant to their understanding and applicability. These matters include interpretation of its basic constructs and that of the notion of evidential independence, the characterization of generalized conditional probability relations, the definition and interpretation of conflicting evidence, and the identification and use of generalized measures of information content.