Learners embark on a virtual trip across the globe while traveling through a substantial timeline to explore hydrology with several experts as guides. Books in the "True Book" series incorporate bold photographs that accompany descriptive text covering science, history, problem solving, marvels in engineering, and exploration. Snippets of significant facts about water aspects are nicely featured by a prominent gold arrow and playful font. Bright colors provide an enhanced study about fascinating sidelights, classic data, and additional mysteries for engaging readers of all ages. Details about the study of water systems, cycles, fresh water sources, weather events, and scientific components (as found in liquids, gases, and solids) are given in a clear manner just as vocabulary is appropriately explained within context. For more intrigue, Find the Truth! presents a true or false introduction to the topic while The Big Truth! segment focuses on an extraordinary feature in greater scope. Helpful sections in all of the books include true statistics, resources, important words, index, and about the author. Within the resources section are listings of several books, organizations, web sites, and places to visit for further study. Students have several guided tours that are both meaningful and on level. As part of the "True Book" series, which follows the same format while featuring a variety of scientists and their captivating careers. Reviewer: Susan Treadway, M.Ed.