An unabridged collection spotlighting the best hard science fiction stories published in 2019 by current and emerging masters of the genre, edited by Allan Kaster. A coastal restoration researcher can help the police solve a murder but is conflicted over the unjust nature of the criminal justice system in "Soft Edges," by Elizabeth Bear. In "By the Warmth of Their Calculus," by Tobias S. Buckell, the captain of a dustship musters her crew to escape from a trap set by Hunter-Killers in a game of cat and mouse amid the rings of a giant planet. An arachnipede becomes wary of potential mates after she sees a male eat her mother . . . but she's lonely in "A Mate Not a Meal," by Sarina Dorie. In "The Slipway," by Greg Egan, astronomers are hard-pressed to explain what appears to be a new cluster of stars that's growing by the hour. Abandoned at a lunar base after losing radio contact with Earth, a newlywed traverses the moon in a buggy with her newborn toward a skyhook on the farside in "This is Not the Way Home," also by Greg Egan. In "Cloud-Born" by Gregory Feeley, children born on a ship from Earth become anxious as they begin to transition to their new lives as colonists of Neptune. An astrobiology postdoc is called at the last minute to remotely navigate a robot searching for hydrogen-based life on Titan in "On the Shores of Ligeia," by Carolyn Ives Gilman. In "Ring Wave," by Tom Jolly, an engineer in a life pod is desperate to join a colony in space after an asteroid destroys Earth. A deep-sea mining company's operation is threatened by a crustacean scientist in "The Little Shepherdess," by Gwyneth Jones. In "Sacrificial Iron," by Ted Kosmatka, a decades long mission to another star is threatened when the two men keeping watch over a frozen crew turn on each other. A teenager seeks to maintain her "Captain" status among her non-traditional lunar family by leading her siblings on a dangerous trek to Neil Armstrong's first footprint on the moon in "The Menace from Farside," by Ian McDonald. In "The Ocean Between the Leaves," by Ray Nayler, the mind of a dying gardener is transferred to another body for three days of closure in a state-run experiment. A robot strives to maintain its energy reserves as it crosses thousands of kilometers underwater to find its way home in "At the Fall," by Alec Nevala-Lee. In "Winter Wheat," by Gord Sellar, a Canadian farmer and his son are at odds on how to cope with a powerful agribusiness promoting its genetically modified wheat. And finally, a resentful submarine pilot is ordered to an undersea research facility to assist with the mining survey of a formerly protected seabed in "Cyclopterus," by Peter Watts.