★★★★½ (4.5/5) Recommended for: All students using Brown’s 6th edition textbook. Not recommended for: Those using a different edition or a different author’s organic chemistry text. Tip: Before buying, verify with your course syllabus that the 6th edition of Brown’s textbook is required. If you have the 7th or 8th edition, look for the corresponding study guide, as problem numbers and content have changed.