Because the 5th edition is the most recent "updated" version, older 4th edition hardcovers are often available very cheaply and contain 95% of the same core physics. Verdict: Is it still relevant?
If you are using the PDF for study, you’ll find that Kraus organizes the universe of EM fields into several digestible pillars: john d kraus electromagnetics pdf upd
Since Kraus was an antenna expert (inventing the helical antenna), this section is often considered the best in any EM textbook. Finding a Legitimate Copy Because the 5th edition is the most recent
The "holy grail" of electromagnetics, presented in both integral and differential forms. Finding a Legitimate Copy The "holy grail" of
How energy moves through vacuums and dielectrics.
Even with the rise of newer books like Sadiku or Griffiths, the remains a "must-read." Its strength lies in its physical explanations. While other books might get bogged down in the math, Kraus always reminds the reader what the fields are actually doing in space.