What books do you guy's advice on this subject? . "Naturkosmetik selber machen". I like the fact that it explains a lot of the principles behind the formulating. It's an introduction in the subject of nature cosmetics, the principles behind the formulating and recipes in one book. But it's in German only! I can read German, but it's cumbersome... Also, it's not that recent anymore... It's from 2012. Is there a lot of progress in the field? New ingredients that we use now? Some advice/tips about good books are very welcome...