Hello everyone, I love reading the posts on PF. I enjoy hearing the experiences and thoughts from engineers, scientists, hobbyists, etc. who love science. I have a question regarding academia: does anyone know how easy or difficult it is to become a professor in a department outside of said candidate's PhD subject of study? For instance, I had a professor at the University of Utah in the Mechanical Engineering department who technically earned his PhD in Physics, but earned an undergraduate degree in Mechanical Engineering (and he's been teaching for 50 years up to the fall semester of 2011!). There is another with a Physics BA, and a Materials Science PhD in the same department. Another has a BS in ME and then earned a Civil Engineering MS and PhD. Is this a common occurrence, or did these people just get really lucky and were able to teach what they love and happen to know a bit about? Just wanted to hear everyone's opinions and experiences. Thanks.