The first part of Philosophy Between the Lines is a simple chronicle of evidence of just how widespread the use of esoteric writing really was from the pre-Socratics through the 18th century:
Melzer presents an impressive litany of important (and not-so-important) thinkers across the centuries, including Cicero, Alfarabi, Aquinas, Erasmus, Machiavelli, Montaigne, Montesquieu, Bacon, Hobbes, Diderot, and Rousseau, who either pointed to hidden meanings in their own writings, or acknowledged esotericism in their reading of other writers. He also presents some clear examples of esotericism in practice, as when Machiavelli in The Prince misquotes a familiar Bible story in a way that underscores the broader critique of Christianity he is apparently making.
This section of the book is wonderfully erudite and leaves no uncertainty that esotericism was indeed a major art that is now all but lost. Melzer points to four reasons for past uses of esotericism. First, it served as protection from prosecution; he notes its widespread use in totalitarian countries like the former Soviet Union and contemporary China. Second, it served to protect the political community from dangerous truths, such as philosophical skepticism about the city’s gods and traditions; third, it served a pedagogical purpose by forcing readers to engage on a deeper level; and fourth, it was used as a transitional strategy for modern writers seeking to undermine dogmatism.
Its greater merit, Francis Fukuyama believes, lies in the final chapter, which explains why esotericism was so important to Leo Strauss.