The most basic books needed for the UPSC civil services exam are the NCERT textbooks. These books provide authentic and reliable information which you can safely use in the IAS exam. Also, they contain information in a simple and lucid language such that anyone can understand and form strong foundations in a subject. Therefore, to start off with the UPSC preparation, it is advisable to start with the basic NCERT textbooks and then upgrade to advanced textbooks if the need arises.
Economics is an important subject in the UPSC scheme of things. It is a part of the General Studies Paper III. It is intricately linked with the development of a country and its polity. Therefore, a solid foundation in basic macroeconomics is essential to clear the UPSC exam. In this page, you can download the NCERT textbook for Economics for Class IX.