His novel Stern A funkt Hilfe ("Star A distress call"), which started his successful career in German science fiction, was possibly first published in serialised form in 1948 (sources differ), but certainly in 1952 as a library edition hardcover.
In 1960 he joined forces with Walter Ernsting (under the pen name Clark Dalton).
Together, they developed the Perry Rhodan series, which has since become the world's largest science fiction series, with uninterrupted weekly publication of a new novel/novella since Unternehmen Stardust in 1961, and a circulation exceeding 1.5 billion volumes.
[2] He also developed the concept for Perry Rhodan's sibling series Atlan, which published 850 instalments between 1969 and 1988.
In the 1970s, health issues caused him to withdraw from Perry Rhodan, but continued to work on other projects.