Look To The Inexeperience Curve
With business audio books an important point needs to really stand out and catch you, because before you know it the reader is on to the next segment. This concept stood out for me the other day while listening to Maverics at Work.
As a leader probably one of the most important things you can do is to walk in stupid every day. You need to keep challenging the organization and yourself to seek out unexpected ideas, outside influences, and new perspectives on old problems. Every day something changes. Look to the inexperience curve. The more you know about something, the more important it is to challenge assumptions and habits that built your success in that area. This will help you think in a new light and drive innovation in your organization.
(By the way - don't confuse leader with manager - they are not related. You don't have to manage people to be a leader in your organization.)