[Page 1051]Truth is a vast topic, the subject of whole treatises, especially in philosophy. Here, the topic will be limited to a discussion of aspects of the truth concept that are particularly salient when considering surveillance. After undertaking a thorough discussion about the various understandings of truth and relativism, this entry will consider the following surveillance contexts: policiary surveillance, benchmarking as managerial surveillance, and targeted advertising through commercial surveillance. The aim of this entry is to provide tools for reflection when assessing a proposal to implement surveillance.