Humanity has left Earth behind and headed across the universe, with spaceships riding the Flow, an extradimensional field that allows vessels to travel immense distances in weeks or months. The Holy Empire of Interdependent States and Mercantile Guilds, or the Interdependency for short, allows far-flung outposts to trade and exist successfully in this almost inexplicable time-space web. But now the entire Flow is changing, separating worlds from one another and threatening to destroy the Interdependency. Three people unite to try to save the Empire as they know it. But others see an opportunity for transferring the power to themselves. VERDICT Scalzi (Lock In) mixes science, history, and politics with sharp action and intriguing characters. Readers will be thrilled to take another wild ride across the universe with the author of the "Old Man's War" series. [See Prepub Alert, 10/3/16.]—KC

The galactic empire of the future is shaped by the Flow—mysterious routes that allow faster-than-light travel to specific points. But now they are becoming unreliable. A scientist, a ship's captain, and the ruler of humanity strive to understand and resolve the danger before whole planets become isolated and perish. Set against them are disbelief, politics, and time. VERDICT With a wonderfully diverse and entertaining cast, award winner Scalzi's (Lock In) new series launch offers the allure of an Isaac Asimov novel, written with modern concerns in mind. (LJ 3/15/17)