Booklist May 2019 Aspiring soap-makers needn't have degrees in chemistry and calculus, because Germany-based soap maker Landmann does all (or most) of the figuring for them. (Still, an adeptness with numbers will help, since ingredients are subject to change given different desired results.) Landmann's explanations are detailed,beginning with a definition, exploring both the language and tools needed, plus additions like fragrances,colorings, silk fibers, and herbs (among others). Very little is left to chance; every one of the 18 projects includes ingredients, color photographs, and instructions, plus frequent hints (saltwater is great for problem skin or acne), alternatives, and informational sidebars. Issues with kids and bathing? Try the recycled and whimsical confetti soap. Natural is key here, and Landmann advocates ingredients like yogurt, cucumbers, and Guinness. At the end, there's a trouble-shooting diagnosis for solving problems like coarse holes and oil layers atop the soap, followed by charts on solid fats and butters, a list of saponification numbers, and sources (skewed towards European companies).-- Barbara Jacobs.