Gr 4–6—This series invites readers to “zoom in” on the smallest items of scientific interest, such as quarks, bacteria, and even tardigrades. Text is broken into chunks with headings, color backgrounds, and plentiful illustrations, diagrams, and occasional photos. A variety of characters comment on the concepts being discussed. Sometimes the comments are funny, such as one hydrogen atom telling another, “Let’s be friends!” as they form a molecule. Readers are encouraged to try related activities at home, like pond dipping and observing water under a microscope. Timelines trace the development of theories and breakthroughs related to atoms, genes, and nanotechnology. Each book ends by comparing the sizes of the various objects or creatures to a human hair. VERDICT A series sure to appeal to budding scientists, those who are fascinated by tiny things, and readers who enjoy a dose of humor with their nonfiction.

School Library Journal