Do you know of a text--preferably in English--whose treatment of the class number formula is based on (or follows closely) the one expounded by Zagier in sections II.8 (binary quadratic forms) and II.9 ($L(1, \chi)$ and the class number) of the aforementioned book? Unfortunately, my command of the German language is not so good yet and, to add insult to injury, it seems to me that Springer Verlag is still to commission a translation into English (or one of the Romance languages) of this notable book.

Let me thank you in advance for your attentive consideration of this question of mine.