This is an encyclopedia. An encyclopedia is a book or numbered set of books containing authoritative summary information about a variety of topics in the form of short essays, usually arranged alphabetically by headword or classified in some manner. An entry may be signed or unsigned, with or without illustration or a list of references for further reading. Headwords and text are usually revised periodically for publication in a new edition. In a multivolume encyclopedia, any indexes are usually located at the end of the last volume. Encyclopedias may be general (example: Encyclopedia Americana) or specialized, usually by subject (Encyclopedia of Bad Taste) or discipline (Encyclopedia of Social Work). This book was published by PowerKids Press .