• The most popular book set for National Dental Board Examination preparation is the Master Dentistry series published by Churcill-Livingstone. It has pretty good reviews and can actually be bought as a set for a reasonable discount.
• A book set that is a close second in popularity for preparation for National Dental Board Examinations is National Dental Boards (Admission Test Series , Part I and Part II) by Jack Rudman. Reviews for these test preparation books, however, are mixed, with some being quite negative.
• Another reasonably popular book set for preparing for National Dental Board Examinations is the two volume set: Review of Basic Science and Clinical Dentistry: Basic Science and Review of Basic Science and Clinical Dentistry: Clinical Dentistry by Marvin Reed, Victor Coury, and Jack Wells. While they don't sell as well as the Master Dentistry series or the Rudman texts, they have better reviews.
  
  Check America's Dental Bookstore, the test preparation section, to find these books on NDBE test preparation for sale.

Besides advising books for review, and important step in preparation for any big test is relaxation. Don't prepare up until the very last minute. Prepare until a reasonable hour maybe the evening or the afternoon before the test, and then you will find you will perform better if you spend the last hour or more relaxing. Remind yourself how much you have learned. Tell yourself that you know the material and that you are confident of your preparation to date. This will lower your anxiety level as you enter the test room and will improve your performance. This advice comes from an expert test taker who aced all of these examinations--the DAT, the NDBE, and many other tests, standardized and others. Get a good night's sleep and come relaxed--you will do much better.