These two twisted debuts will be sure to keep you guessing.   In The Woman in the Window by A. J. Finn, a psychologist gripped by a crippling agoraphobia hasn’t left her Manhattan townhouse in more than 11 months. When she’s not watching old movies, she observes the neighbors and photographs them.  She becomes obsessed with a new family across the park, an obsession that reaches paranoia when she believes she has witnessed a stabbing in their home.    “Once the book gets going, it excels at planting misconceptions everywhere” (NYT).”  Meanwhile, In The Wife Between Us by Greer Hendricks,  an angry ex-wife is stalking a young, innocent fiancee who is a carbon copy of her former self…or so it seems.  Be forewarned—the plot twists in this one could cause whiplash.