Book

A book is a set of written, printed, illustrated, or blank sheets, made of ink, paper, parchment, or other materials, fastened together to hinge at one side. A single sheet within a book is a leaf, and each side of a leaf is a page. A set of text-filled or illustrated pages produced in electronic format is known as an electronic book, or e-book.

Books may also refer to works of literature, or a main division of such a work. In library and information science, a book is called a monograph, to distinguish it from serial periodicals such as magazines, journals or newspapers. The body of all written works including books is literature. In novels and sometimes other types of books (for example, biographies), a book may be divided into several large sections, also called books (Book 1, Book 2, Book 3, and so on). An avid reader of books is a bibliophile or colloquially, bookworm.

A shop where books are bought and sold is a bookshop or bookstore. Books can also be borrowed from libraries. Google has estimated that as of 2010, approximately 130,000,000 unique titles had been published. In some wealthier nations, printed books are giving way to the usage of electronic or e-books, though sales of e-books declined in the first half of 2015.

Blues

Blues is a genre and musical form that originated in African-American communities in the "Deep South" of the United States around the end of the 19th century. The genre developed from roots in traditional African music, combined with European American folk music. Blues incorporated spirituals, work songs, field hollers, shouts, and chants, and rhymed simple narrative ballads. The blues form, ubiquitous in jazz, rhythm and blues and rock and roll, is characterized by the call-and-response pattern, the blues scale and specific chord progressions, of which the twelve-bar blues is the most common. The blue notes (or "worried notes") which are often thirds or fifths which are flatter in pitch than in other music styles, are also an important part of the sound. Blues shuffles or walking bass reinforce the trance-like rhythm and form a repetitive effect called a groove.

Blues as a genre possesses other characteristics such as lyrics, bass lines, and instruments. The lyrics of early traditional blues verses consisted of a single line repeated four times. It was only in the first decades of the 20th century that the most common current structure became standard: the so-called AAB pattern, consisting of a line sung over the four first bars, its repetition over the next four, and then a longer concluding line over the last bars. Early blues frequently took the form of a loose narrative, often relating troubles experienced within African American society.