A book (also code) is one with a connection and mostly also with book cover (envelope) provided collection from printed, described, painted or also empty sheets from paper or other suitable materials. The book is one of the defining achievements of mankind. After all, books began to document history and mythology, and later, religious texts. It gave people together with the mentioned "history" – "chronology", together with "religion" – "education", so we cannot diminish the importance of books not only as a subject, but also as a link in the cultural development of mankind; you can buy cheap articles and read about it in more detail. According to Unesco definition are (for statistics) books Non-periodical publications with an extent of 49 sides or more.  UNESCO fixed in 1995 23rd of April as a world day of the book. 
Besides, single works or big text segments which are concluded in themselves are called book, in particular if they are a part of a tape. This is above all with antique works which exist of zusammengehörigen collections of books, the case – examples for this are the Bible and other normative religious holy writings, Aeneid as well as various antique and medieval historical works.
One calls electronically stored book texts digital books (in English e-book). Another modern variation of the book is the audio book.