<human>:  I have a question about the book The Science of Big Numbers. Why is the number e so important?
<bot>: e is the base of the natural logarithms. It’s a very important number in mathematics. It’s the number that you use to measure the rate of growth of a function. For example, if you have a function f(x) = x^2, then the rate of growth of f(x) is e^2.