Just in time to commemorate the Feb. 2, 1969, death of actor Boris Karloff - best known for his nuanced rendering of Frankenstein's monster in "Frankenstein" (1931), "The Bride of Frankenstein" (1935) and "Son of Frankenstein" (1939) - the horror streaming platform Shudder debuts the documentary "Boris Karloff: The Man Behind the Monster." It's an affectionate, informative and entertaining look at the performer, born William "Billy" Pratt to Anglo-Indian parents (before adopting his stage name upon breaking into Canadian theater, with no training). Along with the many great clips of Karloff from his prolific stage, film and television career (clips that will make you glad Shudder has plans to also stream some of Karloff's classics), this documentary portrait includes interviews with such fans and aficionados as filmmaker Guillermo del Toro, who calls Karloff his "messiah." Appearances by Karloff's daughter Sara, John Landis (co-director of Michael Jackson's "Thriller" video) and such film historians as Leonard Maltin add context and color to the documentary, which despite being heavy on black-and-white archival footage makes for a lively and vibrant appreciation of an artist. Looking back at Karloff from today, in an era in which the horror genre all too often means movies that evoke disgust, Karloff's work in such classic monster movies as "The Mummy" and the noirish "Bedlam" are a refreshing reminder of the actor's greatest strength, which was - ironically, considering the extreme nature of some of his roles - his subtlety. Unrated. Available on Shudder. Contains some clips from scary movies. 99 minutes.