Do you know of a text--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: to add insult to injury, it seems to me that Springer Verlag is still to commission a translation into English of this notable book.

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