Heddy Honigmann has been hailed as the ne plus ultra of documentary filmmakers and been fêted by retrospectives at MoMA and the Centre Pompidou. Her latest opus, an exquisite portrait of the lives of six service dogs and their owners, blossoms into a poignant exploration of the love affair between mankind and its best friend. To be sure, the pooches do amazing things (best seen to be believed), but it’s Ms. Honigmann’s warm sensitivity as an interviewer that earns her the trust of her four-legged subjects and their two-legged co-stars alike, making Buddy the rarest of finds, not just another shaggy dog story, but a heartwarming crowd pleaser from a great humanist filmmaker.