The Chicago-based commercial printer R.R. Donnelley & Sons continues its string of acquisitions with the $412.5 million purchase of Von Hoffman, which specializes in printing educational textbooks. This is Donnelley’s third major buy in recent months; in October, the company spent $1.3 billion on Banta Corp., and another $176 million last month for the catalog printing firm Perry Judd’s Holdings. In a statement which made it into the AP coverage of the transaction, Donnelley CEO Mark Angelson said, “This completes our ‘trilogy’ of transactions designed to offer our print customers greater capacity and flexibility, and further secures our position as the leader in our industry.”