This paper reviews existing research on corporate governance to provide a future direction for research on the corporate governance of Korean companies, which is characterized by concentrated ownership where the pursuit of the private benefit of control by controlling shareholders is not properly regulated. Early research on corporate governance focused on the theoretical backgrounds of the conflicts of interests between shareholders and managers, and Jensen and Meckling(1976) provides a seminal paper that shows less than 100% ownership by entrepreneurs renders them to pursue their own private interests as the costs of such diversion will be shared with other shareholders while the benefit is solely enjoyed by the entrepreneurs. Many empirical studies have confirmed that managers tend to diverge corporate resources, examples including overinvestments and empire building, low level of cash payout policy and free cash flow, tunneling through related party transactions, usurption of business opportunities, hiring family members and relatives of dubious qualification, issuing securities at deep discounts to family members, inappropriate remuneration, etc. In addition to the partial ownership by controlling shareholders, an other line of studies have also confirmed that the disparity between their cash-flow rights and control rights is negatively related with firm values. They show that small ownership itself is not an issue, but the disparity matters since it can entrench managers while their economic interests are not aligned with other shareholders. Holmstrom(1979) and following papers focus on information asymmetry as another source of moral hazard on the part of managers who takes advantage of their superior position in the management of their firms, and maximizes their own interests at the expense of shareholders if they are not properly incentivized or monitored. The issue of information asymmetry accordingly rendered corporate governance research to focus on monitoring mechanisms that are supposedly to enhance the transparency and accountability of firms. Most importantly, the boards of directors are found to play a key role in regulating inappropriate behavior of managers, and numerous empirical studies have confirmed that the level of the independence and expertise of non-executive directors are positively correlated with firm values and performances. Studies on managerial compensation schemes including tenure termination also show that they are mostly aligned with the interests of shareholders as a regulating mechanism even though there exist cases where opportunism by managers can influence the decision process. Corporate governance research on Korean firms has its own advantage since the Korean economy is characterized by business groups, Chaebols, and their ownership structures and managerial behaviors provide ample cases for interesting analyses. Tunneling is a typical phenomenon observed among affiliated firms belonging to a business group where corporate resources of listed firms are diverted to firms mostly owned by controlling families. Research on the diverse cases of diversion by corporate insiders and on the failure of monitoring mechanisms deserve further studies in Korea, which will shed more light on the incentives of corporate insiders in an emerging economy where its legal system does not properly penalize the misconducts of corporate insiders, contributing to the area of corporate governance research, and also to the improvement of the corporate governance of Korean companies.