This is a program announcement (PA) with set-aside funds. The PA is designed to stimulate and support research on sleep disorders in Parkinson's disease (PD) and Parkinson's related neurological conditions (PRNC). Support will be for research on PD and PRNC patients as well as patients in appropriate comparison groups and/or healthy control subjects. Responsive applications could deal with the following areas: natural history of symptoms studies, mechanistic studies of the sleep disturbances in PD and PRNC, associated sleep disorders such as Restless Legs Syndrome (RLS) and sleep-disordered breathing (SDB), and studies of the sleep-related effects of pharmacotherapies for PD and PRNC. The timing and scope of this PA are predicated on recent research and clinical findings indicating promising new directions for the diagnosis and care of patients with PD and PRNC.