There are plenty of books available in the market in the different streams helping the students to have clear concepts in the streams they have chosen. I do recall up my old days when in almost all the subjects, the books were not available in plenty of the different writers but with the change of time, you can have quality of books in the different subjects. There are certain books in the science streams which can strengthen their concepts.
Physics - In Physics written by Sri H.C. Verma is certainly an excellent book. The writer has taken pain to write the different chapters in such a way that the aspirants will have the clarity of the chapters.
2) The aspirants should go through the text books at the first instance so as to have clear concepts of the syllabus prescribed.
3) In Mathematics, the books written by both Sri R.D . Sharma and Sri R.S. Aggarwal are equally good. Sri M.L. Sharma has written the chapters on Mathematics so clearly that the aspirants can refer to this book for both their regular examination of class twelve and for engineering entrance.
4) Chemistry- The book written by Sri O.P. Tandon is quite helpful.
For engineering competition, the book written by R.C . Mukherjee in Chemistry is quite helpful. For Physics, aspirants can refer to the book written by Sri D. C. Pandey.