Digitized emotion almost seems contradictory. Can emotion be simulated through digits? The cold binary codes of zeros and ones may appear in tune to the logic of cognition in the mind perhaps, but can they emulate the emotional affairs of the heart? Claims that emotional activity can be captured, identified, recognised, and potentially simulated digitally have become increasingly prevalent (Fry, 2018; McStay, 2016; 2018). This book draws together relevant philosophies, theories, and models of emotion to highlight some of the ways that processes categorized as emotion are being mobilised by digital technologies. We start with processual, relational, and psycho-social approaches to think about the emergence of emotion and affective life through relations between bodies, collectives and technologies. The book will look at four key areas that are pertinent to the study of emotion in a digital age: Emotion-related artificial intelligence, social media, digital mental health, and surveillance. Emotion is at stake in multiple ways in relation to digitisation and data practices, e.g., the significant increase in technologies designed to be able to identify and interpret emotion. Discussion of the impacts of digital technologies often focuses on the their technical capabilities rather than the underlying social and psychological processes. Moreover, it is often what this means for future life that is discussed; a portrayal of a future digital life acts as the meaning framework for considering digital technologies in the present. Digital technologies are often judged in terms of their potential, from providing more tailored shopping experience through behavioural economics to providing automated work environments. However, analysing life in a digital age through the concept of emotion allows for more breadth and depth of digital activity to be explored, which allows for a sense of psychological life to feature.