Book excerpt: C rossword lovers will welcome this second volume of clever, challenging puzzles by David Levinson Wilk. He has devised 72 crosswords that will test solvers' knowledge of a range of topics, covering a variety of tricky and entertaining themes. For one puzzle, you'll have to know how much every letter of the alphabet scores in Scrabble. In another, words "jump" across black squares, while a third uses the same clues for multiple entries. And, of course, there are plenty of less experimental but equally fun crosswords, with anagrams, puns, hidden words in the grids, and other wordplay.