Heads of state can gain power through democratic elections, inheritance, or force. Traditionally, most heads of state have been male, but some countries now have female leaders. Heads of state may rule for a set term or for life. Some rulers derive their authority from religious positions, while others lead secular governments. The document discusses different categories of current and past heads of state, including their gender, region of rule, and whether they are democratic leaders or authoritarian rulers who hold power for life.