Johns Hopkins amassed millions by trying almost anything that promised to make money--investing in liquor, real estate, coal-mining, fertilizer, and more. He never married, and it was only after he’d retired from most of those businesses that the public saw what he intended to do with his fortune: create a university--including a medical school--and a hospital. Beyond the man himself, how have his institutions shaped Baltimore? Antero Pietila guides us through his new book, “The Ghosts of Johns Hopkins.”