CAG - What It Ought to Be Auditing by P. Sesh Kumar, a retired senior officer of the Indian Audit and Accounts Service, is a bold and timely critique of India's Supreme Audit Institution. Drawing on decades of insider experience. The book questions whether the Comptroller and Auditor General (CAG) is truly fulfilling its constitutional mandate. Why does it audit some areas while ignoring others of far greater consequence? Why are crucial reports delayed until their relevance fades? This work explores missed opportunities in auditing key governance failures-like GST compliance, international taxation, welfare schemes with expenditure in billions, impact of government interventions in MSME sector and judicial delays-while advocating for risk-based, data-driven audits modelled on global best practices like PEFA and lessons from UN audits. More than a critique, the book offers a roadmap for reform, urging the CAG to reclaim its watchdog role and adapt to 21st-century governance needs. Essential reading for policymakers, professionals, and citizens who believe in financial accountability and democratic transparency.