This debate has gotten so old! TBR is the best MCAT content book available for ALL subjects. Some people say TBR Bio or O.Chem may be an overkill, failing to realize the goal is to increase your familiarity w/ words, phrases and experiments that would otherwise be totally foreign. Some of material that appear in TBR's Bio and O.Chem content/passages are things that can appear in an MCAT passage. How do I know? I've taken the MCAT already.