Adam Roberts' fourth novel is his most ambitious yet. In a feat of extraordinary world building he creates a universe where a breathable atmosphere extends out between the planets, where aristocrats cruise interstellar space in biplanes, and skywhals make mysterious distant orbits. Then, with bravura plotting he undermines our own notions of reality and leaves the reader unsure which universe to believe. Gaining a reputation as one of the UK's leading SF stylists and masters of the high-concept Roberts, shortlisted for the Arthur C. Clarke award with his debut novel SALT, confirms his extraordinary potential with POLYSTOM.