Years ago, I had a folder on my laptop that looked like this: project , project_final , project_final_v2 , project_final_v2_REAL and project_final_v2_REAL_use_this_one . I was scared to delete any of them, because I couldn't remember which one had the fix I made on Tuesday. Then a friend and I edited the same file at the same time, and one of us overwrote the other's work. If that sounds familiar, you already understand the problem that version control solves. And the tool that almost...