Circulatory Systems offers a scientifically accurate explanation of the functions of blood and the heart in humans, the lymphatic system, two- and three-chambered hearts, and circulation in lower animals, insects and plants…. This book provides a good source for further research when readers already understand basics of molecules, chemical changes, cell structure, etc. Though this title is less comprehensive and effective in explanation than [Herbert S.] Zim's Blood, [Leo Schneider's Lifeline, or Edith Weart's better-on-cells The Story of Your Blood] …, the coverage it gives of lower plants and animals may make it a useful item. The Digestive System, covering digestion in humans, lower animals and plants, is too technical to be used as an introduction. Readers will need some acquaintance with chemistry and biology…. One chapter discusses a balanced diet and the body's need for minerals and vitamins. The final one deals briefly with hunger in the world, the importance of protein in an infant's diet, and the search for new sources of food—but these vital issues call for greater emphasis. Scientific terminology is given with phonetic respellings for pronunciation; technical words are italicized and listed in the index. This title will be useful since the subject is not treated this extensively elsewhere.