The Savage Discipline by Jesse Travis Scott
Just a few years ago Jesse Travis Scott hiked Colombia's famous Ciudad Perdida, a grueling, mosquito-ridden, all-weather-encompassing, 44 kilometer, 4-day hike through the Sierra Nevada mountains near the city of Santa Marta. The average age of his fellow trekkers was about 27 years old, whereas Jesse was about to turn 43 at the time. This is the type of challenge he relished - Jesse was first awake every morning, rising before dawn everyday to meditate and write a page of thoughts and musing. He ended up being the first in his group by a long shot, the only one close to his pace was a young Dutchman almost half his age.
The takeaway from this experience is that everything in this book is achievable. The practices can be implemented as a whole or in a modular, 'take what you need', fashion. Every single practice, technique, and crazed idea can be utilized to improve yourself and your life in one way or another. The book is written from first-person experience, not hypothetical and the methods and disciplines therein have enabled Jesse to achieve and maintain a successful career across multiple fields and operate at his best both physically and mentally.