Once, after having received a handsome sum of money, I rushed to the bookstore with the intention of buying a copy of every book I could get my hands on; the enthusiasm of the moment overwhelmed me. I filled the shelves of my wall with books from many of the sciences. The topics included sociology, and books on general knowledge. I wanted to begin to read, but I didn’t know how to go about choosing a starting point. I found that different books in the same science tended to overlap each other. I found others to contain little of significance. I consulted some eminent scholars and asked them how I should go about studying. They guided me to a way that has proven to be successful. They suggested that I read only the main reference books in that I study them in depth. All other books, they said, I should leave alone, except when research on a specific issue calls for going to a number of books. I was very pleased with the results; I felt more organized and comfortable in following their simple yet sensible advice.
Never pursue minor issues when more important ones should be dealt with first. Whoever does not know his purpose will have a long and tiring journey that leads to nowhere.