From the reviews of the second edition:
The book under review is the basically unaltered second edition of the original, whose popularity at German-speaking universities has grown continually over the past decade. ... Altogether, the present second edition of this well-established, highly cultured textbook on elliptic functions and modular forms comes with ... remarkable and appropriate improvements, amplifications, and up-datings. ... this text breathes the inimitable spirit of the late Max Koecher, a great mathematical researcher and teacher, and his co-author's effort at communicating and preserving it must be highly acknowledged. (Werner Kleinert, Zentralblatt MATH, Vol. 1129 (7), 2008)
The book provides an introduction to elliptic functions ... . The presentation is excellent: the book always carefully lays the foundations and from there proceeds to substantial results ... while always giving complete arguments. (J. Mahnkopf, Monatshefte fur Mathematik, Vol. 156 (3), March, 2009)