First page I clicked was the Computer Science...Sudoku page. Really?: At each step of the recursion, you try out all of the available options, and as soon as on

First page I clicked was the Computer Science...Sudoku page. Really?: At each step of the recursion, you try out all of the available options, and as soon as one of them leads to the correct solution, you backtrack to the previous step to explore any remaining options there or to try a different option there.