Yukl states at three points within the text that “influence is the essence of leadership”. This is
covered in Chapter 6, which concerns power and influence. Here different types of power are
studied, though the focus is on the French and Raven taxonomy of five types of power: reward,
coercive, legitimate, expert and referent. Guidelines are proposed for using legitimate authority,
reward authority and coercive power. Yukl even describes the tone of voice a leader might use,
which (along with his suggested phrases) could be perceived by the reader as prescriptive.