I have a library of books on EMI/EMC, and Paul's book is recognized by many as gold standard. It offers excellent discussions of nearly every EMC topic, with relevant models and equations, PSPICE simulations, examples, and review exercises.
If you can get only three EMC books, I would recommend Clayton Paul's Intro to EMC, Michel Mardiguian's EMI Troubleshooting Techniques, and William's EMC for Product Designers. They all come from different angles (academic, design, and troubleshooting), but together they serve as a good foundation.
Please be kind and indicate if reviews are helpful.