The main goal of this population-based study is to assess the efficacy of two forms of cognitive-behavioral therapy (CBT) to treat various levels of insomnia symptoms in women with breast cancer: a professionally administered form and a patient self-administered form. It is hypothesized that the two treatment conditions will be associated with significantly greater improvements in sleep, psychological distress, fatigue, cognitive functioning, and quality of life, relative to the control condition (i.e., usual care). It is also hypothesized that the magnitude of effect sizes obtained in association with treatment at each time assessment will be greater for the professionally administered treatment than the self-administered treatment.