Inclusion Criteria:  Insomnia Severity Index (ISI) screening survey score of >=15 (i.e., at least "clinical insomnia," moderate-severe) Independent Living status (or equivalent; if dwelling in a community living facility) Ability to complete (sign) own consent form Fluent English speaker/reader Age 65-90 (inclusive, at enrollment) Fully vaccinated against COVID-19 (if participating during pandemic) Willing to refrain from initiating new therapeutic interventions for issues pertaining to sleep that are not a part of this study protocol for the duration of study participation Willing to maintain existing physician-directed intervention for issues pertaining to sleep for the duration of study participation  Exclusion Criteria:  Cognitive Impairment (a score of <18 on the phone-based Montreal Cognitive Assessment [MoCA] screening evaluation) Has a pacemaker Illicit drug use in the past month (self-report) Diagnosed serious mental health disorder (e.g. psychosis or bipolar depression; self-report) Currently engaged in evidence-based psychotherapy for Insomnia (e.g. CBTi) Cohabiting with a previous participant in the study