For those seeking textbooks on General Relativity (GR) and Special Relativity (SR) that include practice problems and answer keys, several recommendations emerged. "Motion Mountain Vol. II: Relativity" offers partial answers to its problems, making it a useful resource. Einstein's own book, "Relativity," is available online but lacks exercises. For a more structured approach, "Spacetime Physics" by Taylor and Wheeler is suggested for SR, while Schutz's book is recommended for GR. Additionally, Hartle's textbook provides numerous examples, although it does not include full solutions. These resources cater to both undergraduate and graduate levels, ensuring a comprehensive understanding of relativity concepts.