When I visited grad schools junior year (1975), I was told I did not need an undergraduate degree. Armed with that knowledge, I held firm in my negotiations about undergrad requirements, and the Dean of the Honors Program later thanked me for bothering to graduate.
When I did get to grad school, a couple of professors didn't have PhDs. One was my eventual thesis advisor, which was awkward in that he didn't really seem to empathize with certain stresses I was going through. ;)
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Specifics on that include:
Undergrad -- Ohio State
Grad -- Harvard, mathematics
Adviser -- Andy Gleason; I realized he didn't have a PhD in that pre-web era only after I saw his bio for the presidency of the American Mathematical Association
When I did get to grad school, a couple of professors didn't have PhDs. One was my eventual thesis advisor, which was awkward in that he didn't really seem to empathize with certain stresses I was going through. ;)
--------------
Specifics on that include:
Undergrad -- Ohio State
Grad -- Harvard, mathematics
Adviser -- Andy Gleason; I realized he didn't have a PhD in that pre-web era only after I saw his bio for the presidency of the American Mathematical Association