The book “Master of Reality” has the intensity, humour and fierce optimism against all odds of a Mountain Goats song or a live, manic John Darnielle performance. You can’t help but root for the damaged soul who is finding angry, determined salvation through Black Sabbath and Ozzy Osbourne in this brief but powerful book. Darnielle’s assignment, as part of the 33 1/3 record review series of short volumes, was to capture how Black Sabbath’s “Master of Reality” album meant so much to him. He has done that with memorable, heartwrenching effect through the persona of a desperate, confused but still feisty and essentially good-hearted teenager named Roger, who is undoubtedly good portions both of Darnielle himself and of disturbed youth Darnielle encountered in an earlier career as a psychiatric nurse. Roger’s voice and desire to survive life on his own terms, with his own way of bolstering his spirits, is unforgettable.