The article formulates corporate finance as a holistic system of principles, methods, and institutions that ensure the long-term sustainability of a company through the coordination of investment, operational, and distribution decisions in the context of limited resources and risk. It is shown that three interconnected loops — capital structure and financing policies, evaluation and selection of investment projects, and dividend policy and buyback — are united by a common objective function of maximizing value, taking into account the price of risk and information expectations. The article summarizes classical theoretical results on the relationship between value and expected cash flows and risk, the role of tax shields, the costs of financial distress, and information asymmetry. It also examines the contribution of the Russian research tradition, which emphasizes the institutional and legal factors that influence capital value and financing availability. At the applied level, the following are covered: multi-level financial planning (strategic, tactical, and operational), budgeting, and cash flow management, including liquidity buffers and cash gap coverage tools; and others. The article concludes that standardization of capital cost calculation, transparency of assumptions, and replicability of models are essential for improving the quality of management decisions and ensuring the sustainability of capital over time.