In this article, digital libraries and networks are discussed. Digital libraries, a kind of information server on the Internet, have now been realized. Information retrieval is a very important function of digital libraries. Conceptual information retrieval has also been introduced. One direction of the future of digital libraries is the distributed digital library, which integrates digital libraries on the Internet. The distributed digital library is also discussed. The Internet has received much attention in recent years. In this article, data transmission between publishers and digital libraries is estimated.