Do I need to identify a potential hosting department, lab, advisor, or mentor at Harvard before I apply? Does the Society help Junior Fellows find mentors at Harvard?

No, you do not need to indicate a prospective mentor/advisor or hosting department/lab in your application. Junior Fellows in the sciences usually find a host lab at Harvard to conduct their research, but this can be arranged after candidates are elected and the offer is accepted. Other Junior Fellows often find a mentor in their home department, but the Society does not arrange for formal mentorship.