<\body> When a document gets really large, you may want to subdivide it into smaller pieces. This both makes the individual pieces more easily reusable in other works and it improves the editor's responsiveness. An entire file can be inserted into another one using . In order to speed up the treatment of included documents, they are being buffered. In order to update all included documents, you should use . When writing a book, one usually puts the individual chapters in files , until . One next creates one file for the whole book, in which the files , until are included using the above mechanism. The table of contents, bibliography, etc. are usually put into . In order to see cross references to other chapters when editing a particular chapter , one may specify as a ``master file'' for the files to using . Currently, the chapter numbers themselves are not dealt with by this mechanism. You may want to manually assign the environment variable at the start of each chapter file in order to get the numbering right when editing. <\initial> <\collection>