We should point out that this book is submitted in the so-called analytical condolence to the celestial mechanics, which means the solutions of differential equations, which devolves to questions in the form of celestial mechanics chains unfinished often. However, the theory that there is today the most attention, namely how the theory of differential equations, which allows us to know the properties of this function achieved equations without knowing the general solution, and without necessarily resorting to the series-ending.