The Colossus of Maroussi by Henry Miller (1941). Miller spent the summer of 1939 travelling through Greece with Lawrence Durrell, and this is his account of it — rhapsodic, self-absorbed, and genuinely transporting. He barely mentions the islands, but he captures something essential about what Greece does to a Northern European visitor: the light, the sense of time collapsing, the peculiar generosity of the place. The best possible companion for a first Greek summer.
Prospero's Cell by Lawrence Durrell (1945). A memoir of life on Corfu in the late 1930s, written with the same intoxicated love for the Aegean world that fills Miller's book. Durrell is a more precise observer, and his portrait of the island's light, landscape, and people reads as well on Andros as on any other Greek island. His subsequent Greek island volumes — Reflections on a Marine Venus (Rhodes) and Bitter Lemons (Cyprus) — are equally fine.
The Magus by John Fowles (1966). Set on a fictional Greek island clearly modelled on Spetses, where Fowles taught in the 1950s. The atmosphere — the heat, the isolation, the sense that rationality loosens under the Aegean sun — translates perfectly to Andros. Not a comfortable book, but an accurate one about what the islands do to people who spend a summer there.
Sailing the Wine-Dark Sea: Why the Greeks Matter by Thomas Cahill (2003). A readable cultural history that traces how the ancient Greeks shaped Western thought, literature, and the idea of the individual. Visiting Palaiopoli — Andros's ancient capital — makes more sense after reading it. Better as context than as scholarship, but the context is worth having.