There is an increasing lifestyle use of modafinil and other cognitive-enhancing drugs by healthy people (Farah et al., 2004; Sahakian et al., 2015; Porsdam Mann and Sahakian, 2015). In this chapter, we will focus on modafinil and discuss its actions on neurotransmitters in the brain and the neuromodulation of different forms of cognition. We will then review the evidence for modafinil as a cognitive-enhancing drug. In addition, we will discuss the three main reasons for its increasing lifestyle use by healthy people: To gain the competitive edge or superiority over others at school, university, or work. To counteract the effects of jet lag, lack of sleep, or shift work. To enhance motivation for tasks that are perceived by the user as not especially interesting or attractive to complete. We will also reflect on some of the neuroethical issues in regard to the use of cognitive-enhancing drugs by healthy people.