The Evolution Of Cooperation

We based our evaluation of book condition on the following criteria:

* New: Just like it sounds. A brand-new, unused, unread copy in perfect condition.

* Like New: An apparently unread copy in perfect condition. Dust cover is intact; pages are clean and are not marred by notes or folds of any kind.

 * Very Good: A copy that has been read, but remains in excellent condition. Pages are intact and are not marred by notes or highlighting, but may contain a neat previous owner name. The spine remains undamaged.

 * Good: A copy that has been read, but remains in clean condition. All pages are intact, and the cover is intact. The spine may show signs of wear. Pages can include limited notes and highlighting, and the copy can include "From the library of" labels or previous owner inscriptions.

 * Acceptable: A readable copy. All pages are intact, and the cover is intact (the dust cover may be missing). Pages can include considerable notes--in pen or highlighter--but the notes cannot obscure the text.