So many years have passed since the principal of the artificial cloud seeding was discovered by Schaefer (1946) and Vonnegut (1947). And the technique has been used in many countries in order to enhance rainfall amount there. However, many people doubted whether rainfall amount can be increased by using the technique. It is curious situation that some people convince effects of artificial cloud seeding and the others doubt it. The inconsistency is ordinary attributed to diversity of natural clouds. Then we intend to show effects of artificial cloud seeding in conditions as simple as possible to confirm that the technique is always effective in suitable conditions as same as other scientific results. For the simplicity, liquid carbon dioxide was directly injected into developing clouds of super-cooled liquid water particles. And we wrote this book to develop the technique in order to control rainfall amount with researchers who are interested in artificial cloud seeding.