Vallista will be the fifteenth book in Steven Brust's Vlad Taltos series, set in the fantasy world of Dragaera. It will be released in October of 2017. Following the trend of the series, it is named after one of the Great Houses, and the personality characteristics associated with that House are integral to its plot.
This story is rumored to be set immediately before the events of Hawk. Early front-matter material released promoting the book suggests it will feature the character Devera in a larger role than any previous Vlad novel. Much of the story will apparently take place in a mysterious house on the shore of the Greater Sea of Chaos.