Ann Arbor, MI-based Borders Group Inc. is on the front lines of the challenging book and music sales battle, with 360 domestic and 22 international brick-and-mortar Borders locations; about 850 Waldenbooks retail stores; 36 Books Etc. locations in the United Kingdom; Borders.com, a joint venture with Amazon.com; BordersStores.com, devoted to Borders’ retail stores; and PreferredReaders.com, Waldenbooks’ loyalty program. Mary Campbell, Borders’ senior manager of customer relationship marketing, talked with DIRECT recently about e-mail’s role in the company’s cross-channel marketing strategy. Campbell joined Borders four years ago. She previously was with J. Walter Thompson as a media supervisor, and headed up the DM program at Time Warner’s Sunset Publishing continuity division, where she built its gardening program. The move to Borders