This documentary celebrates the bold and surgically funny work of Washington Post political cartoonist Herbert L. Bock, who signed his work Herblock and may have drawn the most caustic, accurate Nixon caricatures ever. It may be a little late to celebrate anything having to do with daily newspapers, but one of the heartening things about this film, based on the many celebrities, newsmakers and newspaper people who weigh in, is just how many people were long-time “Herblock” fans. You hear from Jon Stewart, Lewis Black and Jules Feiffer – and also from famous Post employees Bob Woodward and Carl Bernstein.