There is essentially no difference in the faculty vetting process carried out for open textbooks, compared to commercially published textbooks. As with all textbooks, open textbooks vary in quality. Faculty selection of open textbooks, as in the selection of commercial textbooks, is often a collaborative process driven by departmental faculty. Quality of a particular open textbook can be determined in several ways: 1) recommendations by faculty who have used the open textbook, 2) vetting by faculty reviewers, and 3) faculty use of review guidelines created to standardize the open textbook review process. Some OER sites have a review system built in.