Ingram Industries is big in books and boats. The family-owned company distributes books and handles digital assets through Ingram Content Group, one of its operating divisions. Ingram Content Group consists of book wholesaler Ingram Book , digital content distributor Ingram Digital, and on-demand book printer Lightning Source, among other units geared toward Christian bookshops and libraries. Ingram Marine Group, which operates Ingram Barge, constitutes the company's other operating division. The nation's largest inland carrier, Ingram Barge ships grain, ore, and other goods via a fleet of about 4,500 barges and some 150 towboats.