Which is the best book for JEE Main and Advanced?

While there's no single "best" book that fits every aspirant, here's a breakdown of some highly recommended ones for JEE Main and Advanced, divided by subject and purpose:

Physics

• Conceptual Understanding:Concepts of Physics (Vol. I and II) by H.C. VermaFundamentals of Physics by Halliday, Resnick & Walker
• Concepts of Physics (Vol. I and II) by H.C. Verma
• Fundamentals of Physics by Halliday, Resnick & Walker
• Problem-Solving:Problems in General Physics by I.E. Irodov (Advanced)Understanding Physics series by DC Pandey
• Problems in General Physics by I.E. Irodov (Advanced)
• Understanding Physics series by DC Pandey
• JEE Main Specific:39 Years' Chapterwise Topicwise Solved Papers (DC Pandey)Objective Physics by DC Pandey
• 39 Years' Chapterwise Topicwise Solved Papers (DC Pandey)
• Objective Physics by DC Pandey

Chemistry

• Physical Chemistry: Problems in Physical Chemistry for JEE (Main & Advanced) by Narendra Awasthi
• Problems in Physical Chemistry for JEE (Main & Advanced) by Narendra Awasthi
• Modern Approach to Chemical Calculations by R.C. Mukherjee 
•   
• Inorganic Chemistry:Concise Inorganic Chemistry by J.D. LeeNCERT Chemistry textbooks
• Concise Inorganic Chemistry by J.D. Lee
• NCERT Chemistry textbooks
• Organic Chemistry:Organic Chemistry by Morrison & Boyd (Advanced)Organic Chemistry by O.P. Tandon
• Organic Chemistry by Morrison & Boyd (Advanced)
• Organic Chemistry by O.P. Tandon
• JEE Main Specific:39 Years' Chapterwise Topicwise Solved Papers (Arihant)Problems in Inorganic Chemistry for JEE (Main & Advanced) by V.K. Jaiswal
• 39 Years' Chapterwise Topicwise Solved Papers (Arihant)
• Problems in Inorganic Chemistry for JEE (Main & Advanced) by V.K. Jaiswal

Mathematics

• Algebra:Higher Algebra by Hall and KnightAlgebra by Cengage
• Higher Algebra by Hall and Knight
• Algebra by Cengage
• Trigonometry:Plane Trigonometry Part 1 by S.L. LoneyTrigonometry by Cengage
• Plane Trigonometry Part 1 by S.L. Loney
• Trigonometry by Cengage
• Coordinate Geometry:Plane Coordinate Geometry by S.L. LoneyCoordinate Geometry by S.K. Goyal
• Plane Coordinate Geometry by S.L. Loney
• Coordinate Geometry by S.K. Goyal
• Calculus:Calculus by Amit M. AgarwalDifferential Calculus by Amit M. Agarwal
• Calculus by Amit M. Agarwal
• Differential Calculus by Amit M. Agarwal
• JEE Main Specific:39 Years' Chapterwise Topicwise Solved Papers (Arihant)Play with Graphs by Amit M. Agarwal
• 39 Years' Chapterwise Topicwise Solved Papers (Arihant)
• Play with Graphs by Amit M. Agarwal

Things to Note: 

• NCERT Textbooks: These are fundamental for building a strong base and are essential for both JEE Main and Advanced.
• Previous Years' Papers: Solving these helps you understand the exam pattern and identify important topics.
• Mock Tests: Regularly taking mock tests helps you assess your preparation level and improve time management.

Important:

• - Choose books based on your learning style and current level of understanding. 
• - Don't overload yourself with too many books. Focus on understanding concepts and practicing problems. 
• - Supplement your preparation with good study materials, online resources, and guidance from teachers/mentors.

Remember, the "best" book ultimately depends on your individual needs and preferences.