At the start of this entertaining speculative novel of lost races and time travelers from Roberson (Here, There and Everywhere
), cosmonaut Akilina "Leena" Chirikova, aboard Vostok 7 in Earth orbit, enters a strange silvery gateway to a planet called Paragaea, where a single giant continent and inland sea host dinosaurs and giant sloths, as well as humans and such hybrid creatures as jaguar men, snake men and bird men. Luckily, Leena meets fellow dimension-hopper Hieronymus Bonaventure, a sailor from the Napoleonic era, and his jaguar-man partner, Prince Balam. Together the trio set off across a barbaric alternate Earth worthy of Edgar Rice Burroughs to find someone who understands the dimensional portals so Leena can return home. Roberson's style, in the best pulp manner, favors enthusiastic exposition and travelogue with dashes of swashbuckling. His colorful characters and setting transport readers to a simpler era when every story offered new worlds to explore. (May)