In this chapter, I review psychology's contributions to the study of hope. To close potential gaps in this interdisciplinary volume, I include work in psychiatry and nursing. The nearly 400-year history of psychological reflections on hope reveals extended stretches of neglect, alternating with brief flashes of interest. Shifting scientific paradigms are partly to blame. However, I suggest that the greatest challenge for investigators seeking scientific consensus on the topic may be cultural and sociopolitical. I begin with a review of the most significant writings and research on hope, dating back to the seventeenth century. I examine goal-related approaches in greater depth, due to their strong influence on the field of psychology. The latter half of this chapter is more critical and prescriptive. For a deeper commentary, I rely on Markus's (Meas Interdisciplinary Res Perspect 6:54-77, 2008) distinction between constructs and concepts as well as Danziger's (Naming the mind: How psychology found its language. Sage Publications, 1997) observation on how psychology found its lexicon. This middle, diagnostic section includes a review of philosophy of science criteria for evaluating theories. I transition to general prescriptions for achieving a better understanding of hope, organized around Bacon's "four idols" of the mind, and add specific suggestions for future research. I conclude with a summary of recent work within our hope lab.