What I find particularly interesting is that the editor of this pamphlet and the correspondent in many of the letters is R' Shimon Aryeh Schwabacher, the successor of R' Avraham Kohn of the infamous Temple of Lemberg.
His picture (from his biography Pnei Aryeh - available here)
As you can read in his biography, he was much more moderate then his predecessor. Even so, it is really nice to see that the great Rabbis of the time such as Netziv and R' Yosef Zechariah Stern saw no problem in corresponding with him and even providing all the customary honorifics.
A third volume was promised but to the best of my knowledge was never published.
 A similar case came before R' Samson Raphael Hirsch. You can see his great efforts on behalf of the agunah in a series of letters in Shemesh Marpeh (one can also see the letters sent to R' Hirsch on this case in a separate pamphlet published by Bar Ilan. This was also the subject of the acrimonious correspondence between the Rogatchover and the Seridei Eish. There the Rogatchover castigates the SE for his insistence that we must follow the Rema and Chasam Sofer, (the Rogatchiver refers to them as נמושות ). I see that the Netziv (pg. 63) argues similarly to the SE that:
אפילו אם יש בזה עיגון ודעתי לסמוך על גאוני קרמאי שאין המומרים זוקקים בכ׳ז אחר שהוא ננד פיסקי השו"ע מה אני כשאני לעצמי לצאת בהוראה כזה ומראש כתבתי בתשובתי שהעתקתי כי אפ' בהצטרף דעת גאוני הדור יצ׳ו אהיה נם אני כיהודה ועוד להני תנאי ור׳ שלום ישכון שלום וברכה בישראלbut I am not certain if the cases are identical.
 The "Maskil who was close to the Rabbonim" referred to in the Introduction in the section against the Maskilim was Chaim Zelig Slonimski. Yaakov Reifman also wrote a response to this article which was published posthumously in Ohr Hamizrach by Meir Hershkowitz.