http://www.sinc.sunysb.edu/Clubs/buddhism/nhj/wte.html
Chapter 1
THE PATH OF CULTIVATING ENLIGHTENMENT
There is a story behind this book. An old friend, Mr. Xiao, came to see me. As he was about to leave, he asked me a question: "Shakyamuni Buddha left home when he was 18,[1] and finally--much later, after years of effort--lifted his head, saw a bright star, and was enlightened. What was it that he was enlightened to?"
If it had been someone else who had asked this question, it would not have had any great importance. But Mr. Xiao has been studying Buddhism for many years, so when he raised this question, it was no ordinary matter.
According to what is recorded in the scriptures and the traditional accounts, as soon as Shakyamuni Buddha was born, he was already equipped with an extraordinary natural endowment. Because he had cultivated enlightenment practices through past lifetimes over many eons, as soon as he was born in this life, various kinds of auspicious things happened. He renounced his princely position and left home, and for twelve years he sought enlightenment. Everyone should pay attention to these twelve years, because it is very easy to pass over them lightly.
At the moment we will emphasize the twelve years when Shakyamuni Buddha cultivated various religious practices. At that time there were many Indian religious sects that had been in existence for quite a while, each with its own methods of cultivating practice. Shakyamuni Buddha fully studied the various kinds of ascetic practices and used various methods to cultivate and refine himself.