 This entry has focused mostly on positive information. Formally speaking, negative information is simply the extension-via-negation of the positive fragment of any logic built around information-states. Different negation-types will constrain the behaviour of negative information in various ways. Informally, negative information may be thought of variously as what is canonically expressed with sentential negation, process exclusion (both propositional and sub-propositional) and more. Even when we restrict ourselves to a single conceptual notion, there may be vigorous philosophical debate as to which formal construction best captures the notion in question. In this section, we run though several formal analyses of negative information, we examine some of the philosophical debates surrounding the suitability of various formal constructions with respect to particular applications, and examine the related topic of failure of information flow in the situation-theoretic sense, which may give raise to misinformation or lack of information in particular settings. 