Recent studies have shown that insomnia may represent a vulnerability factor for Major Depression (MDD). These findings suggest that if remitted patients with recurrent MDD received treatment for their insomnia, this intervention might prevent or delay relapse/recurrence, or at least diminish the intensity of subsequent episodes. We propose to evaluate this hypothesis by undertaking a preliminary study on the effects of Behavioral treatment for insomnia on the clinical course of patients with remitted recurrent MDD. Specifically, we propose to randomly assign 45 patients with remitted recurrent Major Depression to one of two conditions behavioral treatment for insomnia (n=30) or to a contract control monitor only group (n=15) behavior therapy was selected because this treatment modality has demonstrated efficacy with respect to insomnia yet is not likely to have direct antidepressant effects. Sleep and depression symptoms will be monitored on a weekly basis prior to treatment initiation (3-4 weeks), during active treatment (8 weeks), and for a period of up to 33 months. Monitoring will require that subjects complete daily sleep diaries, weekly Beck Depression Inventories (BDI), and monthly clinical interviews. The BDI will be used to ascertain when subjects exhibit a worsening of their depressive symptoms and will serve as a prompt for a clinical evaluation to determine whether there has been a relapse/recurrence. Weekly diaries will be used to determine 1) the acute effects of the insomnia treatment, 2) the long term efficacy of the behavioral intervention, and 3) the extent to which sleep related complaints are prodromal to new onset episodes. Monthly interviews will be used to monitor and confirm clinical state. In addition, polysomnographic (PSG) data will be acquired prior to and following treatment. These data will be used to rule out occult sleep disorders (e.g., sleep apnea and PLMs), to objectively assess severity of insomnia symptoms prior to and following treatment, and to explore, in a preliminary way, the extent to which sleep architecture variables (e.g. reduced REM latency) independently predict treatment outcome, clinical course, and/or how these measures interact with self report sleep continuity measures. It is hypothesized that behavioral treatment for insomnia in patients with remitted MDD will be associated with less depressive symptomatology during remission, longer periods of remission, less severe new onset episodes and better responses to treatment for recurrent episodes Data for each of these hypotheses will be used to calculate effect sizes and to conduct power estimates. These analyses, if they provide good feasibility data, will be used as the foundation for a R01 level application. Ultimately, If one or more of these hypotheses are borne out in the larger follow up study, this will strongly suggest that 1) CBT for insomnia may be an important strategy for the management of recurrent MDD, and 2) insomnia is not only a symptom of MDD, but also a factor in the development of the disease.