This intricate narrative follows a disembodied consciousness orbiting Earth as part of Project Travel Light, a solar energy experiment in which--we slowly gather--a bed of algae aided by solar ""windmills"" somehow nourishes a former human brain. The organ has been removed from the diseased body of a project engineer and implanted in an I(nterplanetary) M(onitoring) P(latform), its sensory functions closed down or replaced by equivalent artificial data transmissions. Four months into the project, Imp Plus awakens to an altered awareness in which a handful of human memories and words seem strangely keyed to unaccountable new perceptions, unexpected physical growth, and a dawning distrust of Ground Control. The situation is transformed into weird richness by McElroy's painstaking attention to the mental dimensions of minute physical processes. As Imp Plus begins to perceive its own malfunctioning ""body"" in microvisual detail, we follow the clues to what has gone wrong at the uncharted level of molecular ""experiences."" The betrayed cyborg gropes among colors, shapes, feelings, and movements recording the very processes that support the brain: glucose metabolism, oxidation, ionization. The gradual derangement of Imp Plus (a medical puzzle pieced together only at the end) is observed with the lurid precision of brilliant microphotography. McElroy's slow, demanding traceries of awareness do not always escape tedium; it is the price of the strange and valuable task he has set himself. An exhausting, disorienting work of discovery.