Used vs new: which should you buy?
For International Relations, used copies are the default choice unless the course requires a bundled online access code — codes are single-use and do not transfer with a second-hand book. Used copies of a current edition typically sell for a fraction of the new price, and condition grades of "good" or better are usually fine for a textbook you will mark up anyway. Buy new when the book includes required software or code access, or when no used copies of the correct edition are listed.
Rent or buy?
Compare the rental fee against the used price minus what you can sell the book back for. If buying used and reselling costs less than renting, buying wins — and you keep the book. Renting makes sense for expensive current editions in courses outside your major. Our rent vs buy calculator does the arithmetic.
Can you use an older edition of International Relations?
Prices for the previous edition usually drop sharply once a new one ships, while the core content changes modestly. The deciding factor is whether your assignments reference specific page or problem numbers, and whether the course relies on an online homework platform tied to the current edition. Ask your professor before committing — and see our guide to older and international editions for what typically differs.
Getting the right edition
Search by ISBN rather than title. Publishers reissue textbooks every two to three years and each printing carries its own ISBN, so a title search mixes editions together. Paste your syllabus ISBN into the box above and every store link updates to that exact printing.