Its mission was to develop an overall conceptual framework of US generally accepted accounting principles (US GAAP).
For Interpretations see section 9551 of the final edition of the APB Accounting Principles, Volume 2, Original Pronouncements as of June 30, 1973.
The interpretation numbers come from the Financial Accounting Board's Original Pronouncements as amended 2008/2009 Edition, volume 3.
Also, consult this volume for detailed listing of amendments, deletions, and other changes to the individual interpretations prior to 2009 (when the Accounting Standards Codification was issued.)
Also, consult Fasb Pre-Codification AICPA Copyrighted Standards for those Interpretations (AIN-APB 9, 18, 20, 21, 26,and 30) that were finally superseded by the Codification.