>No there are most certainly no Phd programs that take two years (most take between 5 and 10 years) - what might be a confusion is that you can complete most if not all of your course work in about two years but then you have a year to study and take your general exams and two to three years to do your research and write the dissertation, and this is for the US system - Bertrand, didn't you tell me that in France it can take up to 15 years to complete a Phd, with all of its teaching requirements?<
In the UK a Phd tends to take between 3 and 4 years full-time. By full-time I mean that during that time students generally don't do other jobs but just work on their Phd. For part-time students the time is doubled. Occasionally people do manage to get a Phd in two years full-time study but they generally have a masters already which is where they may have begun the research interest that they then developed for the Phd so really it's still 3 years. I'm curious though about course work etc. In the UK a Phd is entirely research and then you write your thesis. There is no course work or exams here. As for teaching requirements, there are none but most Phd students will do a few hours part-time lecturing here and there to gain experience. cheers, Sol.

