A book is a written or printed work of substantial length, whether physically made of paper and bound with covers, or digitally encoded as an ebook. It may be a fiction (containing invented content, often narrative) or nonfiction (containing content intended as factual truth). Books have long attended the preservation and dissemination of knowledge in every literate society. The very act of reading elicits an emotional and intellectual reaction to the text, which is often informed by its genre, the commercial transaction it underwent, the cultural context within which it was crafted, and the manner in which it is presented on its pages.
Although the material forms and provisions of books have varied greatly over time, the basic characteristics remain the same. A book is designed for communication of information and ideas, and it has been adapted to the needs of every literate culture. It is portable, containing both durable and removable content, and is accessible to a wide range of readers, even though the twin requirements of portability and permanence might exclude temple columns with inscribed messages or posters fixed on immovable objects.
Books come in many shapes and sizes, and their form and contents have changed with changing technologies. The arrival of new publishing business models has caused a rethinking of the notion of the book, and new text formats have emerged that challenge traditional definitions.
An ebook is a digital version of a book that can be read on an electronic device such as a computer, tablet, or smartphone. A book in the format of an e-book may contain all or part of a text, images, music, or video. An e-book can also be created by combining multiple documents, including word processing files, spreadsheets, presentations, and scanned images.
The term book is derived from the Latin verb boka, meaning to write. The written texts in books were originally created using the minuscule alphabet of the Phoenician and Egyptian languages. Later, the Greek alphabet became the standard. In medieval times, books were created on vellum and parchment, while the printing revolution in Europe during the 15th century led to a great number of printed books that were published as single volumes.
The book as an object has been studied in the academic disciplines of textual scholarship, codicology, bibliography, palaeography, art history, and social history, among others. In studying the physical properties of books, such as where and how they were kept, how they were handled, and the ideological and religious beliefs of their owners, scholars have gained insights into the communication of text and the role they play in the lives of people. This is the core of a new discipline called book studies, which is now an acknowledged area of study. It is the basis of modern library science and bibliography. It also provides the foundation for the study of early printed and digital texts, and the development of new publishing methods such as print on demand and e-publishing.