The post office started to create souvenir sheets in 1933 in a special printing for the "American Philatelic Society Convention". They have continued throughout history till this day. Very popular among collectors are "Sheets" with movie and movie stars theme. Among the hundreds printed to this date are "Sheets" from the movie Star Wars, and "Sheets" with movie stars like Judy Garland, Cary Grant, James Dean, Marilyn Monroe, Humphrey Bogart, James Cagney, Edward G. Robinson, Lucille Ball, Audrey Hepburn, John Wayne, Henry Fonda, James Stewart, Bette Davis, Bob Hope, Gary Cooper, Katharine Hepburn, and Gregory Peck. Another great collectable theme are cartoon characters such as Porky Pig, Bugs Bunny, Sylvester & Tweety, Daffy Duck, and Wile E. Coyote & Road Runner. Other great themes would be Sports or "Sheets" on the ecology of the U.S. There are Chinese New Year themes, and "Sheets" with artists. You could almost pick a subject and find the Post Office printed a "Sheet" on that subject. Collecting different sheets is easy and fun. I will show a few examples of "Sheets" with different themes.