One great book is 'The 7 Habits of Highly Effective People' by Stephen Covey. It teaches valuable principles like being proactive, beginning with the end in mind, and seeking first to understand then to be understood.
'Mindset: The New Psychology of Success' by Carol Dweck is also excellent. It shows the power of having a growth mindset rather than a fixed mindset and how it can transform the way you approach challenges and learning.