As glimpsed by director-interviewer Matthew Diamond, Paul Taylor is at once a brutal task-master, insecure about his work, and overall, a somewhat remote human being, owing to a solitary early life in foster care. But a pure love of the dance is the unifying, invigorating force for him and his company, and we are the beneficiaries in this candid, behind-the-scenes look at a bona fide artistic institution.