This free app is extremely diverting and addictive. It’s a bit like Scrabble in that you must string adjacent letter tiles to form words. The longer the words, the more points you earn. You also get bonus points by using special tiles as they become available, but beware the flaming tiles that will burn down the library if you don’t use them fast enough! And, there is a greater goal than just amassing points; you climb the library succession ladder from encyclopedia salesman to trainee to clerk to scribe and so on with the passing of each level. Great interface.