When the British composer Max Richter premiered Sleep in London in 2015, the concert lasted all night with audience members reclining on beds. That’s because Sleep is designed to induce just that. It’s not just that the piece for piano and strings is soft, gentle and reassuringly consonant, or that it lasts eight hours—long enough, in other words, to last until dawn. While composing the piece, Richter consulted with sleep neuroscientist David Eagleman, folding cutting-edge research on slow-wave phases of sleep—states crucial to learning and memory—into the very shape of the work. The slow tempo is intended to have a lulling effect, drawing listeners into drowsiness and holding them there. In the opening movements, the music’s repetitive nature and recurring themes are subtly hypnotic, assisting listeners in clearing weary minds; as the piece goes on, instrumental and vocal outlines are worn away, leading to a quasi-ambient fog to accompany deep sleep. Mastered in Spatial Audio in 2022, every moment of this album’s sublime beauty is heightened and intensified without, of course, ever taking away from its restorative central premise. And for listeners who don’t want to miss any of that, a companion album, From Sleep, excerpts the most striking movements in a comparatively brief, one-hour dosage—enough time, perhaps, for a relaxing cup of tea.