There are array of civil services preliminary examination books that will help you in preparing well for this exam. Some of them are as follows –
a. For general science you can refer to class IX and X books
b. Advanced science books that are published by Tata McGraw Hills
c. For current news papers like The Hindu, The Economic Times, and The Times of India
d. Magazines and periodicals like Frontline, Business Today, Business Outlook, and Yojana
e. Competitive Magazines like Chronicle, Competitive success review, and Pratiyogita Darpan
f. For History and Indian National Movement like Class IX for Contemporary India, India and Contemporary World I, and India and Contemporary World II
g. Indian History book published by V.K . Agnihotri
h. Indian and World Geography books like Fundamentals of physical geography, and India Physical Environment
i. Class XI books for beginners for Political science books and political theory
j. Class XII Indian constitution
k. For economic Indian Economy for Civil Services Examinations by M.Laxmikanth.
l. The other books are Our Constitution , by D.D. Basu, Our Constitution, and Our Parliament both authored by Subhash C Kashyap, Indian Polity For UPSC: 3rd Edition by M.Laxmikanth.