This chapter provides a terminological overview of ‘topic’ and ‘topicalization’. It looks back in linguistic history to identify major contributions to research on topics as linguistic units and describes aboutness and givenness as major criteria to define what a topic is. Building on the study of topics, the chapter introduces topicalization in detail by revisiting previous definitions of topicalization and identifying a relatively wide definition as ideal for the study of Asian Englishes in particular and World Englishes in general. Topicalization is defined as the marked fronting or preposing of syntactic constituents other than the subject that is employed by speakers for discourse-pragmatic reasons. Major functions of topicalization are creating emphasis, contrast, and continuity as well as shifting the topic.