Former First Lady Rosalynn Carter will join Joshua Shenk, author of "Lincoln's Melancholy: How Depression Challenged a President and Fueled His Greatness" for a special conversation at the Jimmy Carter Presidential Center. The conversation will be today at 7:30 p.m. in the Carter Center's Ivan Allen III Pavilion. The lecture and book-signing is free and open to the public. Seating is limited and on a first-come, first-served basis.