Walter Cronkite IV is a journalist in his own right, working as an associate producer for CBS News. But he's also paying tribute to that other Cronkite you may have heard of — grandfather Walter Cronkite — in his new book "Cronkite's War: His World War II Letters Home." Cronkite and historian co-wrote Maurice Isserman wrote the book, which contains a selection of letters from the hundreds that Cronkite penned to his wife, Betsy, during World War II. Cronkite and Isserman will discuss the letters and sign books at the National Press Club on June 4 at 6:30 p.m. General admission costs $5, plus a service fee.