Actress Valerie Harper, known to most as the character Rhoda, first in the series "The Mary Tyler Moore Show" and then in the spinoff "Rhoda," will be speaking before a National Archives audience Tuesday about her new book that's -- not surprisingly -- entitled "I, Rhoda." The event will take place at 7 p.m., with doors opening at 6:15. Free tickets will be distributed to the first 250 people in line at the Special Events entrance on Constitution Avenue and Seventh Street Northwest. Those not admitted can join the crowd for a book signing at 8 p.m. The program will also be webcast. The event coincides with the Archives' exhibit Searching for the Seventies: The DOCUMERICA Photography Project, which is free and open to the public until Sept. 8.