The goal of this study will be to assess the effect of SLE on long-term HSCT and breast cancer survivors, and to determine the feasibility and acceptability of SLE as an intervention for CRF. The approach will be informed by the procedures that Ancoli-Israel and her colleagues developed for their research on SLE treatment for breast cancer chemotherapy, as well as by Redd's studies of CBT to treat adjustment disorders in survivors of HSCT. The study arms will test the efficacy of two different types of light treatment, bright white light and dim red light. Outcomes will be assessed through standardized measures of CRF, sleep quality, and quality of life.