Lenovo has just announced plans to acquire IBM and Motorola businesses for a total of more than billion. Of the IBM deal, Wharton management professor Michael Useem , co-author of Boards That Lead: When to Take Charge, When to Partner, and When to Stay Out of the Way , says Lenovo’s board of directors “has helped that company go from a company we have never heard of 15 years ago to the number one personal computer maker in the world.” Useem, who is also director of Wharton’s   Center for Leadership and Change Management , recently sat down with Wharton lecturer Robert Borghese, a corporate attorney in private practice in Philadelphia, to discuss his new book, co-authored by Ram Charan and Dennis C. Carey. In this interview, Useem explains why monitoring is no longer the only responsibility of the board, where board directors should draw the line in their leadership of organizations and where some companies and boards are getting it right, including Lenovo.…