What is the difference between Cengage and the "Black Book" for Maths?

"Black Book" (usually referring to 'Advanced Problems in Mathematics' by Vikas Gupta & Pankaj Joshi) and Cengage serve slightly different purposes.

• Cengage: This is a complete package. It contains detailed theory, solved examples, and practice exercises all in one place. It is designed to be a primary textbook for learning concepts and then mastering them.
• Black Book: This is purely a problem-solving book. It contains a collection of high-quality, challenging problems aimed at students preparing for the JEE Advanced. It has minimal theory and is meant to be used for rigorous practice after you have already cleared your concepts from a textbook like Cengage or your coaching material.

Conclusion: You use Cengage to learn and practice. You use the Black Book to test and perfect your problem-solving skills for the advanced level. They are not direct competitors but can be used sequentially.