Are Arnold Sommerfeld's books still the go-to for understanding the Universe?

[Hetware]

Recently I was reminded of a series of textbooks by Arnold Sommerfeld. When I was a young man, these were obligatory offerings at any respectable bookstore. I never purchased them because I had other things on my plate. Now I cannot seem to find them in print.

I did find this assessment of these books:

http://math.ucr.edu/home/baez/physics/Administrivia/booklist.html

"Arnold Sommerfeld: Lectures on Theoretical Physics
Sommerfeld is God for mathematical physics. "

I always assumed that Sommerfeld's books were required reading for anybody who is anybody in understanding (the) Universe. Can these books be resurrected?

 

[Bobbywhy]

Hetware, do these look familiar?

https://www.amazon.com/dp/0126546622/?tag=pfamazon01-20

https://www.amazon.com/dp/0126546703/?tag=pfamazon01-20

Cheers,
Bobbywhy

 

[Hetware]

Hetware, do these look familiar?

https://www.amazon.com/dp/0126546622/?tag=pfamazon01-20

https://www.amazon.com/dp/0126546703/?tag=pfamazon01-20

Cheers,
Bobbywhy

Yes, but they are only a couple. IIRC, there were six or more volumes.