The clue is "quarrel," and the four-letter answer begins "s-p-a"; but is it "spar" or "spat"? This is a crossword dictionary, to be sure, but this book also helps beginners learn the most often-used words in crosswords (and their clues) and shows them how to avoid common tricks and traps. Based on an exhaustive analysis of published puzzle grids, here is an alphabetical list of the 1,001 most common crossword entries, plus individual guides to such frequently used subjects as mythology, Nobel Prize winners, popes, singers, rivers, words from foreign languages, and even The Simpsons.