Letter Never Sent (Criterion) continues the home video rediscovery of thetoo-often-overlooked Russian auteur Mikhail Kalatozov, director of the Cannes Palme d’Or winner “The Cranes are Flying” (1957) and the almost unclassifiable “I Am Cuba” (1964). This 1959 film, about a geology team searching for diamonds in Siberia, is a curious hybrid: a Soviet propaganda piece of heroic scientists working for the good of the country turned into a riveting survival drama when they are overcome by a raging forest fire. The lush forest landscape becomes a burning alien wasteland and Kalatozov’s camera makes delicate dollies through the burning brush and wispy smoke, creating beauty from the devastation. Kalatozov seems to take the assignment in stride, giving lip service to the propaganda so he can engage with the primal survival drama, which is where the film burns bright and deep. Blu-ray and DVD. No disc supplements but there is a booklet with an essay by film scholar Dina Iordanova.