Author and coauthor of an incredibly useful series of physics books.
My "like" of post #1 refers of course to Walter Greiner's series of textbooks, which helped me in many many ways.
His passing is a sad loss.
From his book on "Relativistic Quantum Mechanics", I learned clearly how to manipulate Dirac matrices for the first time.
From his book on "Field Quantization", I was able to understand for the first time what Feynman diagrams really are, and how they arise as terms in a perturbation series.
There are many other examples -- too many to list here.
Perhaps it's now time to re-purchase his entire series of textbooks. They benefited from more frequent updates than many other texts, though at the cost of often-changing page and section numbering.
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