This paper reviews literatures related to auditor independence and audit quality. The review is structured based on the four main threats to auditor independence, namely client importance, nonaudit services, auditor tenure, and client's affiliation with CPA firms. For each of the threats, we discuss findings related to the incentives, perception, and behavior of the auditor and the client, the effects of each threat on actual and perceived quality of audit and financial reports. We conclude that inconclusive evidence together with recent changes in auditing profession provides opportunities for further studies on auditor independence and audit quality issues.2