I am an advanced undergraduate student, and I still remember the days when I could open my mathematics textbooks, read through a few sample problems, and then blaze my way through the exercises with little or no help. Come university, and my freshman year, and things changed dramatically. I could still more or less blaze through the Resnick and Halliday exercises, but I was beginning to see that textbooks such as Griffiths, Purcell, Marion and Thornton (I mean, sophomore and beyond) contain exercises I could never solve on my own. In the majority of the cases, I've had to rely on solution manuals to work my way through the problems. It's not like I don't understand the solutions - once I understand the solutions, I can again blaze my way through similar calculations, but for some reason, every problem is different and poses new challenges. I have been wondering if I have reached the pinnacle of my academic ability. Are there really students who could simply take a look at those problems and figure out the answers instantly?