The best economics book for class 12 for detailed knowledge is "Introductory Microeconomics" by Sandeep Garg. This book is published by Dhanpat Rai Publications and is widely used by students across India.

Comprehensive Coverage:
The book covers all the topics of microeconomics in detail, including demand and supply, consumer behavior, producer behavior, market equilibrium, price determination, and market failure. It also includes practical insights and case studies that help students understand the concepts better.

Easy Language:
The author has used simple and easy-to-understand language, which makes it easier for students to comprehend and retain the concepts. The book also includes diagrams and graphs to explain the concepts visually.

Exam-Oriented:
The book is exam-oriented and provides a lot of practice questions and solved examples, which help students prepare for their exams. It also includes previous years' question papers and sample papers, which give students an idea about the exam pattern and marking scheme.

Additional Assistance:
The book is accompanied by a free CD that contains additional study material and sample papers. The CD also includes interactive quizzes and games that make learning fun and engaging.

Conclusion:
In conclusion, "Introductory Microeconomics" by Sandeep Garg is the best economics book for class 12 for detailed knowledge. It covers all the topics of microeconomics in detail, uses simple language, and is exam-oriented. It also provides additional assistance through a free CD.

Firstly i should....preffer ... Sandeep Garg's ..latest addition.... and then try....T.R Jain..