Android maintains search histories for the Google search widget, market, etc. but you can't EDIT past searches. You can't do variations of previous searches by changing or adding a word to the past search. You can't correct a typo in a previous search.. The only option is to re-type the entire thing, while the phone displays the previous search with the wrong character, but not letting you fix it.. Personally, this is one of the most frustrating things about Android. Google is all about searching, but they certainly got it wrong with Android's built-in search..