Partial differential equations and spectral theory Book

I devoured this in two days. The final essay The Indispensable Opposition by Walter Lippman was outstanding. Lippman writes, "For, while the right to talk may be the beginning of freedom, the necessity of listening is what makes the right important......What matters is not the utterance of opinions. What matters is the confrontation of opinions in debate." This collection of essays was a fine example of this kind of substantive exchange of ideas regarding religion, freedom of conscience and feminism.