Word Search Puzzles for Young Einsteins

All puzzle fans have done normal word search puzzles, where they are given a list of words and just have to search the diagram and circle each one when they find it.

But these puzzles are in a different league. Get your brain into gear, because not only do you have to hunt down the words, but you also have to do something either before of after you start looking...For example, - in Hidden Riddles, you must read the leftover letters to answer the riddle. - in Missing Letters you try to work out which letter was removed from each listed word before you can locate it on the grid.