Two volumes of World War II memoirs may appeal as much to parents—for whom the war was reality—as to their teenagers, for whom it is merely history…. [Johanna Reiss's The Upstairs Room and Maia Wojciechowska's Till the Break of Day] both offer straightforward, not-to-be-missed accounts of what it was to leave childhood abruptly behind as Europe entered and endured world war.

Their victory-over-adversity themes are nothing new. But they present them with such disarming freshness and candor that it is difficult sometimes to remember the authors are drawing on 30-year-old memories….

Maia Wojciechowska was 12 when Germany invaded her native Poland in 1939. From then until the family went to America in 1942, her life became a series of personal vendettas against the Nazis that belied both her age and sex. She reveled in fear and danger, flirted with the idea of her own early death, and seemed to...