A Practice Note describing indemnification of and advancement of expenses to directors and officers of Delaware corporations. This Note provides an overview of Section 145 of the General Corporation Law of the State of Delaware, including an explanation of permissive and mandatory indemnification under that statute. This Note also discusses undertakings to repay advanced expenses, a corporation's statutory authority to purchase directors and officers insurance, and the indemnification of and advancement of expenses to employees, agents, and other covered persons.