Books & samples paper for NDA?

To do best in any examination, one needs to choose the best books for preparation. For Mathematics parts, RS Aggarwal's Quantitative Aptitude for competitive examinations and Mathematics for NDA/NA: National Defence Academy and Naval Academy are best for preparation recommended by Experts and top educators. For General Ability Test, you may rely on books such as Science and Technology in India by Kalpana Rajaram, Social Problems In India (Indian Society GS1) by Ram Ahuja, Objective General English for Competitive Exams by SP Bakshi, General Science Guide for Competitive Exams CSAT/ NDA/ CDS/ Railways/ SSC/ UPSC/ State PSC/ Defence by Disha, History Of Modern India by Bipan Chandra. Following these books will help you a lot. Other books like Study Package for NDA/NA Entrance Exam by Tata McGraw-Hill Education India can also be followed. Check out this link http://competition.careers360.com/articles/best-books-prepare-for-nda
You can download previous years' of at least last 5 years NDA Exam papers from the link given below http://competition.careers360.com/articles/nda-question-papers Solving these papers will help you a lot in understanding the exam pattern.