<p>This review offers a thorough examination of a comprehensive and accessible analysis of photon subtraction, elucidating its theoretical foundations, experimental advancements, and transformative applications in quantum technology. We delve into the quantum mechanics of photon subtraction and highlight the pivotal role of beam splitter operations in quantum state engineering. Robust theoretical models and well-defined mathematical frameworks illustrate how photon subtraction transforms Gaussian states into non-Gaussian states, thereby facilitating the generation of non-classical resources essential for quantum information processing. This review investigates recent progress in experimental research, focusing on innovations in detection technologies and scalable, integrated photonic platforms. By synthesizing recent developments and their broader technological implications, this review underscores the significant contributions of photon subtraction to advances in quantum communication, computation, and precision metrology.</p>