The Financial Accounting Standards Board (FASB) establishes and improves standards of financial accounting and reporting. FASB standards are officially recognized as authoritative by the American Institute of Certified Public Accountants (AICPA), and the Securities and Exchange Commission (SEC).
Other organizations that help determine accounting standards include the Public Company Accounting Oversight Board (PCAOB) and the Government Accounting Standards Board (GASB), the International Federation of Accountants (IFAC), the International Auditing and Assurance Standards Board (IAASB), and the International Accounting Standards Board (IASB).
Standards are conventions, rules, and procedures necessary to define acceptable accounting practice at a particular time.
GAAP, or Generally Accepted Accounting Principles, are a set of guidelines for companies to aid in preparing financial statements according to a standard.
GAAS, or Generally Accepted Auditing Standards, are auditing standards for auditors to help ensure transparent and unbiased auditing.
Wiley GAAP 2016
Wiley Practitioner's Guide to GAAS
Wiley Not-for-Profit GAAP
Wiley GAAP for Governments 2015