This book was given to me by my former supervisor at the university I attended and worked during my undergrad years, and though it is short, it makes great points and offers simple advice to better oneself in all aspects of life including professional, academic, and personal relations.
I often reference this for my professional development:
"Service is the lifeblood of any organization. Everything flows from it and is nourished by it. Customer service is not a department... it's an attitude." This reinforces the way I try to live my life, as stated by Aristotle: "We are what we repeatedly do. Excellence, then, is not an act, but a habit."
For growth professionally and academically, I like to remember that, "If you will spend an extra hour each day of study in your chosen field, you will be a national expert in that field in five years or less."
For personal relations, customer service, or just persistence, I remember it's that one degree that makes a difference: At 211 degrees water is hot. At 212 degrees it boils."
"The drops of rain make a hole in he stone not by violence, but oft falling."
This short book is full of inspiration and work a stay on any bookshelf.