Books That Have Influenced Pastors

Barna recently released a study of the books pastors name as most helpful to them as leaders. I was encouraged to see authors like John Piper and John MacArthur, but discouraged to see others, like "Seventh-Day Adventist icon Ellen White". I'd like to see pastors reading fewer books on leadership and more books on theology, apologetics, church history, and other subjects that would make them better leaders in the process. The books mentioned in Barna's study seem to be short-hindsighted. There doesn't seem to be much interest in church history and biographies of past church leaders. Instead, there's a lot of interest in present lives and present trends. If these pastors are reading books that don't have much depth, the people under them have to be even shallower. The immature sheep keep getting a lot of attention and all of the milk they want, but anybody who wants more meat has to go out on his own to get it. It doesn't look like they'll get much from their pastors.