Stephen Jay Gould was one of the writers I read as a teenager that changed my world view and way of thinking for the rest of the life. And I don't even like baseball, even now :) Such a clear thinker.
clear thinking; his deep ideas he returned to again and again - history of deep time, punctuated evolution, the implications of human evolution not being a climb towards some teleological end but of complexity gradually increasing with time. The incredible degree to which evolution and biology "take advantage" of contingent happenings.