This book introduces the history and meanings of various Japanese words with shared roots. Based on the insights of Professor Emeritus Shizuka Shirakawa ( 白川静), a leading kanji scholar, it also has cute illustrations to help readers visualize the links between the words introduced.
For example, the component おも appears in many modern Japanese words. As this book explains, おも originally comes from the word 面, meaning "face." The verb 思う, which means "think" or "feel" spontaneously, is derived from this root. おも (face) developed into おもう (think, feel) because your face usually expresses your spontaneous thoughts or emotions.
If you already have intermediate to advanced reading skills in Japanese, and you are looking to improve your Japanese word knowledge by delving into the etymology, this book is a useful resource!