Dear All, first of all I want to say thanks for this great forum!, which I am following since many years ago. I have never participated, but I have read almost everything for years hehe. But I currently have a personal issue, which I would not talk about with my colleagues and which is affecting me a lot. Therefore I decided to register and to share it with you. It is long, and therefore I thank you in advance for reading! Here is my story: I am currently an Assistant Professor in a east european university, which is one of the best of my origin country and also my undergrad alma mater (I have been here for one year) At high school I was a rather mediocre student at a rather mediocre school. I have to say that I was always bad taking exams, which I attribute to the fact that I am really a non-constant worker and I never finished learning all the material corresponding to an exam. I fought against this for years without any success. But well, somehow, and against all predictions of my teachers, I got very good results in the final national school exam and managed to get into one of the best universities of the country, the university where I am an Assistant Professor now (I was the second last in the list!). As an undergrad, I had a weak start, since my background was not the best, but I eventually got the rhythm and, although I was not consistently the best one, I managed to be on the top in several subjects and I finally graduated in the best 20% of the generation. Again, I was not constant in my studies and therefore could never answer all the questions appearing in the tests. I continued fighting against this, without success. But well, with the results I obtained, I qualified to apply to some research fellowships to go to Germany (where some great groups in my field of interest were located!). Of course, my chances were small, but I still qualified and of course applied!. Somehow, I managed to convince everyone I was the one! and I got all fellowships to which I applied, even when people with much better grades were also applying (I was the first one in the list of selected people for all fellowships I applied to!). I spent 2 years researching at different universities and finally went to a top 3 german university where I did my PhD (also with a german fellowship). In Germany, the PhD does not include attending any classes and I spent 4 years only doing research, learning from books, attending conferences and talks, etc, etc. During this time, I learned a lot and somehow filled some of the gaps that I had from my mediocre performance as an undergrad (at least these related with my research topic). I published a lot, got an excellence prize from the faculty (as recognition for outstanding performance during the PhD) and finally graduated with summa cum laude (highest possible honor). With these excellent results, I was recruited for my current position and here is where my problem begins. As I already mentioned, I was not really a good student as an undergrad and I do have the feeling that there are many things I do not really know. Since as a PhD student I was only focussed on research, I feel I did not have the chance to really fill the gaps that I have in my background and now I have to teach these undergraduate courses, which I passed with not so high scores. Although I am now able to understand every single equation appearing in the textbooks of the subjects that I am teaching, and to solve all problems I can found on them, I needed a lot of time to prepare my classes, since I do not really dominated everything before reading the textbook. So, my problem is that I have the permanent feeling that there are several things I do not really know. This feeling is disappearing in the subjects I am teaching, but there are other several related subjects where the feeling stays. This situation frustrates me a lot, since I do not have the time to relearn everything, and it is therefore interfering with my research activities, and life in general, since I spend a lot of time thinking about this, get anxiety, etc. Additionally, I think I have an issue with my poor grades as an undergrad. Currently, I am getting lots of applications of top students attracted by my CV, which, on the paper, looks very impressive (Also, several Senior Professors here see me as a very promising young talent and recommend top students to work with me). These students have much better grades than what I got as an undergrad (although they do not know that), and somehow this remember me all the things I do not know. The only thing that probably helps me is that talking with these students I realize that I know much more about science in general than they know. This helps me for a while, until the bad thoughts begin again =(. So, I am not really sure what I am searching for telling you all this. I guess I just want to know your honest opinion about my situation. I thank you in advance for any comment you could give me.