信件是传记作者的金矿；它们揭示了官方记录所隐藏的东西。

计算复杂性的美在于它能够根据问题的固有难度对问题进行分类。

People are always blaming their circumstances for what they are. I don't believe in circumstances. The people who get on in this world are the people who get up and look for the circumstances they want, and, if they can't find them, make them.

Open your eyes, look within. Are you satisfied with the life you're living?

我们可能变老了，但音乐让我们保持年轻的心。