Promised Messiah and Imam Mahdi Hazrat Mirza Ghulam Ahmad as) says "
Our books are complied after due research and after a full analysis of facts. They are designed to draw seekers after truth to the path of truth. They must reach people who happen to have been infected by hostile writings, some of them on the brink of spiritual ruin. Especially must those countries receive our books and receive them soon which happen to have been infected most dangerously by the poison of misguidance, so that all those interested in a search of truth have the books soon enough in their hands. This purpose cannot be served if we decide to push the publication and circulation of books only through sales. A business outlook in such a matter in any case seems unworthy and objectionable."
(Victory of Islam, Page 45, Published in 1891)