Read this book alongside a standard text like Dummit & Foote or Lang. Seeing the historical concrete view next to the modern abstract view provides a complete understanding.

If you're interested in learning more about Galois theory, we recommend the following texts:

Edwards strips away the layer of mid-20th-century abstraction. Instead of defining a Galois group as an automorphism group of an abstract field extension, Edwards looks at it the way Évariste Galois did: as a group of permutations of the actual, concrete roots of a specific polynomial. 2. Deep Historical Context

Those interested in how the theory was actually discovered.

Edwards avoids immediate abstraction. He begins exactly where the historical problem started: solving polynomial equations. You study the actual roots and the algebraic relations between them. This makes the transition into group theory feel earned and logical. 2. Constructive Mathematics