The practice of meditation is believed to have existed well before written history. Today, the growth of research on meditation and the development of new applications incorporating meditation are advancing exponentially. This rapid expansion is due to the efforts of clinicians, theorists, and researchers — all of whom are interested in legitimizing meditation research by secularizing the various practices, translating them into clinically relevant interventions, and examining the effects of meditation on biological outcomes such as brain structure and function, immunity, and stress hormones. And yet, there is much more to know.