If you want to save money, most of the university courses I've found online that list this book as their text also mention that the 7th ed. is fine. Mine was the same. Email your prof before classes start and see if the seventh will do. There's probably an old pdf they can give you with edition-correct suggested problems for each class. Don't buy the solutions manual--solutions for it (and the 7th) are on slader.<br><br>The book itself is pretty great if keeping textbooks is something you like to do. It is comprehensive (and heavy!) and has lots and lots and lots of exercises for each section, which is a wonderful thing when something only kinda-sorta makes sense and you need to practice. Plus, the questions start easy and scale reliably. It only has solutions to odd-numbered questions.