Several good books are available for CBSE Class 11 Maths, but the best book may vary from student to student, depending on their individual needs and preferences. However, some of the popular books recommended by experts are:

1. NCERT Mathematics for Class 11
2. RD Sharma Mathematics for Class 11
3. Mathematics for Class 11 by RS Aggarwal
4. New Simplified Physics: A Reference Book for Class 11
5. Arihant Mathematics for Class 11 by Amit M Agarwal.

It's essential to choose a book that provides clear explanations and sufficient practice problems and covers the entire CBSE syllabus. Students should also refer to the NCERT textbook, as it is the primary source of the curriculum and exam preparation.