This essential textbook, 'Modern Physics' by Ahmed Ali Obaidullah, published in 2014 by Dar Safa for Publishing and Distribution, offers a comprehensive exploration of the pivotal concepts that define contemporary physics. It is meticulously structured to guide university students through the complexities of special relativity, quantum theory, atomic structure, and nuclear physics. The book provides clear explanations, detailed derivations, and practical examples to build a strong conceptual understanding. It serves as an indispensable resource for students and educators seeking a solid foundation in the principles that have reshaped our view of the physical world, making it a cornerstone of any physics curriculum.