Diagnostic imaging is founded on physics and technology that transform anatomical and physiological signals into clinically meaningful images. Volume 1 introduces imaging physics, basic modalities (radiography, ultrasound, CT, MRI), image formation principles and radiation safety fundamentals. It explains equipment operation, image optimization, artifacts recognition and quality-control practices that underpin reliable interpretation. Practical chapters guide modality selection for common clinical questions and outline basic protocol design. Emphasis on safety, contrast use and patient preparation ensures responsible imaging practice. The handbook is designed for trainees in radiology, clinicians ordering imaging studies and allied health professionals involved in imaging services.