is this book good for studying e&m and general relativity?
Yes, this book and the whole series ( L&L )are top of the line. These books are to be revered as classics.
The e&m part would be a good supplement to the second half of a graduate course. The gr part still has some unique material, but there are better introductions.
i mean as a continuation of studying GR if you have already had the basic introduction to it.
As Helios says, CTF is a classic, but if your intent is to get up to speed for GR research, I'd recommend continuing on with modern GR books like Carrol, Stephani, or Wald. Then perhaps a book like A Relativist's Toolkit or Advanced General Relativity .
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