A textbook is a book of instruction. Its primary aim is not to impart information about a specific subject but to enable one to develop proper understanding of the subject. Presentation is extremely important and it is prepared to serve a particular level of readership. It cannot be comprehensive. Often presentation is colorful and attractive, giving plenty, of illustrations and diagrams. A good text-book takes into consideration the method of teaching and level of readership. It is revised keeping in view new development and changing methodology of teaching. There is a difference of opinion about the place of textbooks as treaty sources.Example:
- Textbook of crop production, by P.C. Raheja, etc., Bombay, Asia. 1973.
- Textbook of cytology by Walter V. Brown and Eldridge M., 2nd ed. Bertke, St. Louis, Mosby, 1974.
- Theory of Cataloguing, by Girija Kumar and Krishan Kumar, 5th ed, Delhi, Vikas, 1986.