What is biotechnology and how is it related to the problems of treating AIDS, preventing the development of cancerous tumors, and creating useful plants invulnerable to pests? The editors of "Question Mark" receive many letters with requests to answer these and many other questions related to the rapidly developing new scientific discipline - biotechnology, especially recently. The book’s text has been translated from the original language using an artificial intelligence system. In most cases, the translation is accurate and clear, but occasionally there may be incorrect phrasing or individual words left untranslated.