Authenticity has been recognized as a central concept in the ethics of human enhancement. In the last decade, a plethora of novel distinctions, specifications, and definitions of authenticity have been added to the debate. This chapter takes a step back and maps the different accounts of authenticity to provide a nuanced taxonomy of authenticity and reveal the emerging underlying structures of this concept. This chapter identifies three kinds of conditions for authentic creation and change of the true self (coherence, endorsement, and relations) as well as ways how the true self should be expressed (in one's self-conception, self-presentation, and one's body, emotions, and actions). Based on this analysis, this chapter discusses the hopes and concerns human enhancement raises for authenticity. Enhancement technologies do not threaten or foster authenticity across the board but affect different dimensions of authenticity individually. Finally, this chapter turns to the value of authenticity and argues that the debate on authenticity in the ethics of human enhancement would profit from a more extended discussion on the comparative value of the individual dimensions of authenticity.