I have tried vainly to understand the significance of the following statement attributed to David Hilbert:

$\textit{" The theory of complex multiplication is not only the most beautiful part of mathematics but also}$ $\textit{of the whole of science"}$

as quoted by J.S.Milne at the beginning of Sec.15 'Complex Multiplication for Elliptic Curves' in his book "Modular Functions and Modular Forms'. Can anyone throw some light on this comment, especially its second part?