The Chef's Knife, also known as the Cook's Knife or French Knife, is arguably the most essential tool in any kitchen. Ranging in size from 6 inches to 10 inches, this multi-tasker is well suited for slicing, dicing, chopping and mincing, and can handle everything from a watermelon to shallots - and almost anything in between. When choosing a chef's knife, select the one with the largest blade you are comfortable handling, as the larger the blade, the more useful the knife.