Postcards aren't just for commemorating vacations, they also make for invaluable social history. Tom Ray and Ray Bonis uncover an amazing treasure trove in their revealing new book about vintage postcards, “Greetings From Richmond.” The authors write in the foreword: “Many of the images include buildings and structures that either no longer exist or have since been altered.” But this isn't just a compendium of forgotten vistas, it also gives us a bit of insight into how Richmond once saw itself, and what the outside world found interesting in River City. Expertly researched, and awash in both the familiar (St. John's Church, the Jefferson, Linden Row) and the lost (Cohen's grocery store, the old Chamber of Commerce building, Libby Prison), “Greetings From Richmond” reminds us that there's another great thing about postcards — they make good bookmarks. Ray (of the Library of Virginia) and Bonis (of Virginia Commonwealth University's Cabell Library) will speak and sign their new book at the Library of Virginia at noon Dec. 15. The event is free. 800 E. Broad St.