This is an interesting booklet, and I must state at the outset that I am writing about books and publications in my library. It is not my purpose to get into the question of whether gelatin is or is not kosher.
Rabbi Kopul Kahana was born in Eisiskes, Lithuania, in 1895, studied in Lithuanian yeshivos and was a Rabbi in Lithuania. He came to England before the Second World War and enrolled at Cambridge University to study law. From 1946 to 1968 he was a lecturer in Talmud at Jews College, London. He died in 1978.
The question of whether Gelatin is kosher seems to have been a subject of much halachic discussion in the mid to late 20th century. In 1954 Dayan Yechezkel Abramsky had ruled that halachically bone gelatin was kosher, but did not want this used generally for fear that the psak might be misinterpreted. In 1966 the American Rabbonim, Moshe Feinstein (included in Igros Moshe, Yoreh Deah II) and Aaron Kotler issued responsa allowing gelatin from kosher slaughtered animals, and this was followed by Dayan Grossnass of the London Beth Din and Rabbi Kopul Kahana approving of Gelatin made of chrome leather. In this process, chrome-tanned shavings from leather production are de-chromed and used to produce gelatin.
This booklet was printed by the Narod Press in Whitechapel in 1966, but is not included in Moshe Sanders list of Narodiczky productions.
Jewish Miscellanies 
There was another teshuvah on Gelatin published as a pamphlet by Dayan Krauss of Manchester – I used to have a copy….I recall he was also matir.