Monroe The Monroe Free Library will hold a book discussion of Caleb Carr's "The Alienist" at 7:30 p.m. on Tuesday, Oct. 18. The period thriller describes the hunt for a serial killer in 1896 New York. Keith Walters, a professor at Lehman College and Rockland Community College, will lead the discussion. Copies of the book are available from the library. For more information, call 783-4411.