"The five-second rule, told to children by generations of mothers, says that if you drop a cookie on the floor, you have five seconds to snatch it up before germs swarm over it and render it unsafe to eat. Microbiologist Maczulak uses this bit of home-spun wisdom to introduce readers to the world of bacteria, viruses and fungi. As the author reminds us, many of the manifold creatures in the microscopic world are needed for our bodies to function normally; only a relatively small number are pathogens. Maczulak reveals the current thinking on how long you're contagious when you have a cold, what's the dirtiest room in the house (not the bathroom) and why your doctor is right in refusing to prescribe antibiotics for the flu. Maczulak's writing can be repetitious and unfocused. Nevertheless, addressing such questions as whether or not to use disinfectants, and with sidebars listing food-borne microbes and antimicrobial essential oils, this may prove a helpful home companion. As to that cookie: as grandma always said, just brush it off." Publishers Weekly (Copyright Reed Business Information, Inc.)