It's no wonder that Sylvia Mader's Biology continues to be a text that's appreciated as much by instructors as it is by the students who use it. The ninth edition is the epitome of Mader's expertise: Its concise, precise writing uses an economy of words to present the material as succinctly and clearly as possible, thereby enabling students -- even non-majors -- to understand the concepts without necessarily asking the instructor to explain further. .