It [his dissertation] was the work of a largely self-taught man. I had completed my studies relatively quickly in four university years, from 1947 to 1951, that is, in the difficult time following the end of the Second World War. Afterwards, the circumstances prevailing at the time had obliged me to spend some time first in Church work (1951/52) - the resulting experience was very valuable - and then, though not by choice, in the textile industry and in sales management (1945/6 and 1953/4). ....This Telegraph obit fills in the details nicely. The Times Online has another excellent obit.
During this all too brief novitiate in critical study at Tübingen, which only lasted for two and a half years, the sword of Damocles was always hanging over me: the threat that I would have to go back to industry. With a heavy heart, I left Tübingen in March 1957 and thought it would be for ever. I had written up about twenty per cent of the material and had made excerpts of the most important sources -- there were no photocopies at that time! I took my manuscript and materials with me when I returned of necessity to the completely different environment of industry and management, firmly -- I might almost say, desperately -- resolved, whatever happened, to finish the work I had begun. That I succeeded in doing this -- in spite of inexpressible difficulties, far from the university with its many stimuli to study and its abundant library resources and following a totally different and very exhausting profession -- I owe to a very great extent to the understanding, encouragement and patience of my wife.
The work that I submitted as my dissertation in 1959 appeared in print in 1961....I have placed this little autobiographical look at the past at the beginning of the English translation because this work is for me personally very much more than simply a first book that was followed by others in a relatively straight line. What I learned from it was an intimate association with ancient Jewish and Graeco-Roman sources and it was perhaps good that, for reasons of time and because many books were not available to me, I had to concentrate principally on those sources. At the same time, quite contrary to all human expectations, it also determined my future way of life and made it possible for me to return at the end of 1964 to the historical and theological study that I loved so much.
Update: Roland Deines has published an excellent tribute on the SBL site here; David Neff has a Hengel retrospective at CT; HT: Mike Bird.