Street-smart teen Larry Witherspoon was found dead Monday at the Michigan Avenue branch of the Chicago Public Library, his urban know-how useless to him in the unfamiliar environment. 'Unfortunately, the skills Larry had developed on the mean streets of Chicago's South Side did him no good in a place like this,' librarian Mary Ross said. 'Hypothetically, he could have located a book on library survival skills, had he known what the Dewey Decimal system was and how to use it.' 