Written from the perspective of a practising company lawyer, this work is principally concerned with two broad duties owed by directors of British and Australian companies: to act honestly, in good faith and for proper purposes; and to exercise care and diligence. Public attitudes towards directors have altered since the mid-1980s, and the business community has raised its expectations of directors. In response to this shift in public feeling, parliament and the judiciary are adopting a new approach to directors' duties, widening the scope of duties imposed on directors and encouraging a more rigorous approach to corporate governance. This text analyzes this new approach, with reference to English and Australian case-law, and explores the courts' attempts to deal with the myriad of competing interests found within the morass of legal rules, equitable principles and statutory enactment which comprise modern company law. In examining modern case-law and legislation, the author addresses some of the more contentious and controversial issues which directors in the 21st century will need to confront in order to properly discharge the legal, equitable and statutory requirements of their office. The subject of directors' duties is of theoretical and practical importance, from economic, political as well as social perspectives. This text should be of use to all lawyers, policymakers, academics and researchers working in this complex and rapidly changing field of the law.