This chapter discusses the role of nudge interventions, which are interventions that modify the choice architecture without intervening in the actual choice set. We use nudges when we make subtle changes to the way choices are presented to individuals (the choice architecture). Such small changes are expected to encourage predictable behaviour and assist individuals in achieving goals that they desire. In general, it refers to interventions that, while preserving individuals' freedom of choice, steer them in a specific (socially desirable) direction, thereby improving welfare by assisting individuals in achieving welfare-improving goals (as judged by themselves). Individuals can continue to make whatever choices they want; they can always opt out of a default environment that steers them. Nudges preserve choice and can have a significant impact on our behaviour. They are appealing because they influence behaviour without using regulation or monetary incentives, and they are relatively inexpensive interventions. This chapter attempts to provide an overview of how to change the choice architecture by utilizing well-established cognitive biases discussed in this book.