AMG REVIEW: One of two related albums that R. Stevie Moore recorded in 1973, Monotheism is a series of untitled improvisations for keyboards. (Most are instrumental, although Moore's then-girlfriend Johna Lynn sings wordless soprano vocals on a few and Moore himself adds goofy improvised lyrics here and there; "Monotheism 22" is the one exception, an overdubbed chorus of Moore singing a kind of mock hymn.) Monotheism was mostly recorded on a grand piano belonging to Moore's father, legendary Nashville session musician Bob Moore, and despite the lo-fi limitations of the homemade recordings, that characteristic warm, full sound of the instrument stands out. Other tracks were recorded on electric piano and synthesizer, giving them a period feel that's not without its charms. Overall, however, Monotheism should not be taken for any more than what it is: a collection of brief instrumental improvisations that occasionally veer into plain aimless noodling but more often sound like preliminary scraps that might eventually be worked into songs, or what Moore's hero Brian Wilson used to call "feels." (In fact, one passage of "Monotheism 8" bears a striking resemblance to a song Moore would record over a quarter-century later called "Dewey Decimal System.") Approached with properly adjusted expectations, Monotheism has an offhand, casual charm.

–Stewart Mason, All Music Guide