Ley remained unconvinced by this skeptical attitude. When he was old enough he studied astronomy, physics, zoology and paleontology at the University of Berlin. Ley explained, "I was never quite sure whether my studies would earn me the title of "zoologist" or "geologist," but I kept exploring, in a manner of speaking, looking especially into such corners as others had neglected." He then became interested in spaceflight after reading Hermann Oberth's book "Die Rakete zu den Planetenräumen ("The Rocket into Interplanetary Space")". Although it was a technical book that was difficult to understand, Ley worked through the calculations and concluded that outer space would soon become the next great frontier of human exploration. Ley was so convinced by Oberth's book that he sat down at the age of 19 to write a popularization of its contents. He also began corresponding with every known rocket enthusiast in Europe, including Oberth himself. After publishing "Die Fahrt ins Weltall ("Travel in Outer Space")" in 1926, Ley became one of the first members of Germany's amateur rocket group, the "Verein für Raumschiffahrt" (VfR – "Spaceflight Society") in 1927 and wrote extensively for its journal, "Die Rakete ("The Rocket")". Ley would eventually become the group's Vice-President during a time when it had no active President. Meanwhile, he was writing hundreds of short articles about rockets for German and foreign newspapers.