This is a personal development book that was originally published as a 24-week correspondence course in 1912, and then in book form in 1916. That’s why it had 24 parts of contents in the book with questions and answers attached at the last page of each part.

Favorite quote “Nurture your mind with great thoughts; to believe in the heroic makes heroes.” – Disraeli

Every success had a pattern in it, we can see it in every successful people's life; they’re focus and determined to achieve their goal. Multi-tasking and doing something with a divided mind reduces the quality and the efficiency of any task.

The master key significantly improves your life, as long as you take the few minutes a day to practice as the author suggests.