My father was a mechanical engineer, who didn't get a PhD for an unusual reason: He finished his dissertation before he finished his coursework. In the mid-1950s, he was hired by Penn State to do a specific piece of research on diesel fuels, and the university told him he could use it for his dissertation. It was expected that it would take him three years and he finished it in 18 months. It was published, and on the strength of it, Shell Oil offered him a job at three times the salary Penn State was paying him. He went to the registrar's office and asked if he had enough credits for a masters in mechanical engineering (he already had one in math). He was told he needed one more course in ME and he asked if the course in diesel injection design would suffice. When he was told it would, he said "Give me credit for it, since I taught it the last time it was offered."