The so-called "Treasury of Analysis", my dear Hermodorus, is, in short, a special body of doctrine furnished for the use of those who, after going through the usual elements, wish to obtain power to solve problems set to then involving curves, and for this purpose only is it useful. It is the work of three men, Euclid the writer of the "Elements", Apollonius of Perga and Aristaeus the elder, and proceeds by the method of analysis and synthesis.