Claire Boiko. A science fiction play set in the 25th century. Aliens from Mars plan to invade Earth (20th century). Martian commander Think-Tank deciphers a nursery rhyme book — mistakenly thinks 'Mistress Mary, quite contrary, grow your bells' means Earth has weapons (bells). Invasion cancelled in fear! Librarians preserved books — a book (nursery rhymes) inadvertently saved Earth. Theme: Knowledge (even misunderstood) has power; literature saves civilizations.