Honestly, I have taken Developmental Life Span Psychology, College Algebra (when I had not taken math in years), Western Civ II and Criminal Investigations all in one summer. The Life Span course was a lot of reading--about 4 chapters per week, there were quizzes every week as well, and forum posts every week. College algebra just about killed me, I was glued to my computer doing homework, I was literally in tears, the book is worthless, the tutorials online are worthless, and I spent literally 8-9 hours just doing math, and sometimes I had to redo the same problem over and over and over again because I kept getting the answer wrong. Western Civ was a breeze, but Criminal Investigations required a lot of writing, had quizzes, forum posts and a 7 page final essay in the end, and we had a quiz every week. Your classes MAY be tougher; however, considering I had to teach myself math along with everything else, I'd say my courses may have been even more time consuming than yours. The thing is, it's not about what, it's about when. My life-span course was summer C, it overlapped the entire summer. Math was summer A, and western civ and criminal investigations was summer B. So I was focused strictly on math and life-span for the first half of summer, the second half I was focused strictly on western civ, criminal investigations, and the second half of life-span. This made it doable. If you were about to tell me that you were going to try to take all four in Summer A, or Summer B... then FORGET IT. If you have split them up well enough for them to be in sections, separate from each other, then it's doable. Summer is NOT hard, but it IS time consuming, BUT it's doable. I have a 4.0. I am actually planning on taking four classes this summer as well, 3 of which are science courses, one even has a lab. But I have them split up between summer A (first half of summer), summer C (the entire summer), and summer B (the second half of summer) so they are spaced out much better. Don't let anyone tell you you can't do something. You have to be Okay with the fact that you will be doing homework all day, every day, and you will not be going out with friends, etc. As long as you're ok with having no life, you'll manage. Also, being that you won't have to teach yourself math like I did, all you have to really do is read the chapters, and refresh the material before the tests/quizzes. Your schedule will be much easier than mine, just go for it.