[1]: https://archive.org/details/IrodovProblemsInGeneralPhysics
[1]: https://archive.org/details/IrodovProblemsInGeneralPhysics
Landau's books[0] are very famous among advanced undergrads and grad students of Physics in India.
Landau also measured the genius of his contemporaries[1]. He gave himself a 1.5, and 1 to Schrodinger, Satyen Bose, etc. Eisnstein was 0.5. (Lower the better)
He also won a Nobel Prize in Physics in 1962.
[0]: https://en.wikipedia.org/wiki/Course_of_Theoretical_Physics
[1]: https://bigthink.com/surprising-science/landau-genius-scale-...
However I also remember trying the book and after some failed starts really getting into it and it became one of my favorite books. I believe the difficulty was because the book was purely problems, there was almost no context of theory. But the problems were very well designed and solving them was a joy.