Nineteenth-Century Music (California Studies in 19th Century Music)

This book makes me feel like a muslim: it's so great to have a book which holds the truth, where every question is answered, correctly, completely, and with new openings. The only difference is that with Dahlhaus, that is the case.
Perhaps also endearing, although that may not be the first idea to come into mind with an old German professor. But the way Dahlhaus treats Beethoven and Rossini: he clearly loves Beethoven and deep down thinks less highly of Rossini, he nevertheless tries to treat them both with equal respect.
A modern classic, a book that has become a concept in musicological circles ("The nineteenth-century book"). Indispensible.