Several recommendations for modern physics books suitable for undergraduates include "The Road to Reality" by Roger Penrose, though it becomes technically challenging after the initial chapters. For relativity, "Black Holes and Time Warps" by Kip Thorne and "Black Hole Blues" by Janna Levin are suggested. In quantum mechanics, George Gamow's "Thirty Years that Shook Physics" and Richard Feynman's "QED: The Strange Theory of Light and Matter" are highlighted for their accessibility. The discussion also notes a lack of popular science books on condensed matter physics. Overall, these selections aim to introduce key concepts in modern physics without the complexity of traditional textbooks.