Hmm not sure what you mean by relevant here. I'll take a crack at my interpretation: Is DSP still relevant - undoubtedly yes. Is the book still relevant? Becaus

Hmm not sure what you mean by relevant here. I'll take a crack at my interpretation: Is DSP still relevant - undoubtedly yes. Is the book still relevant? Because it focuses on the underlying theory and concepts and not so much on language specific implementations, I'd say yes to that as well.