REDSHELF, which sells digital textbooks to college students, has raised a $4 million Series B from Coniston Capital and existing investors, including the National Association of College Stores, TechCrunch reports. The Chicago-based company partners with roughly 500 educational bookstores to offer e-textbooks at discounted prices compared to their printed counterparts.The company, founded in 2012 told TechCrunch that it plans to use the funding to expand its cloud-based e-reader platform and its content partnerships.