Discussion with Tim Weiner, author of "Enemies: A History of the FBI" (Random House). Tickets $15, reception following. At 5 p.m., Quogue Library, 90 Quogue St.; 631-653-4224, ext. 4, quoguelibrary.org
Emily Giffin reads from her new novel, "Where We Belong" (St. Martins Press). At 7 p.m., Book Revue, 313 New York Ave., Huntington; 631-271-1442, bookrevue.com.
East Hampton author Dava Sobel discusses "A More Perfect Heaven: How Copernicus Revolutionized the Cosmos" (Walker & Co.). Tickets $15, include beverages and hors d'oeuvres. At 5 p.m., Hampton Library, 2478 Main St., Bridgehampton; 631-537-0015, hamptonlibrary.org.
Joan Cergol and Ellen Schaffer discuss "OHEKA Castle: Images of America" (Arcadia Publishing). At 7 p.m., Book Revue, 313 New York Ave., Huntington; 631-271-1442, bookrevue.com
New York Times journalist Liza Klaussmann reads from her debut novel, "Tigers in Red Weather" (Little, Brown), At 7 p.m., Books & Books, 130 Main St., Westhampton Beach; 631-998-3260, booksandbookswhb.com