“The Testaments” is not, repeat is not, a sequel to Margaret Atwood’s revolutionary dystopian novel “The Handmaid’s Tale.” Indeed it could not follow that classic novel’s trajectory, if only because the TV series has usurped the plot. Instead Atwood reexamines the perverted, horrific world of Gilead, commencing a decade and a half later, and switching from a claustrophobic single viewpoint to three interwoven narratives, two of handmaids and one of ruthless Aunt Lydia. Atwood is among the world’s most assured novelists, each word and sentence carefully chosen, and the story zips along pleasingly. By the halfway point, one spies an overall arc and then races to uncover the dramatized endgame, and the overall read is intriguing and satisfying. But the deep immersion in political terror that “The Handmaid’s Tale” engendered is missing and the plot-driven structure distanced this reader somewhat from any of the three characters. If you’re a fan of the original, this is a must-read, but “The Testaments” will surely not sit as the same class of classic.