L-S interaction, or spin-orbit coupling, is a key concept in atomic physics and quantum mechanics that describes the interaction between an electron's spin and its orbital motion. To gain a solid conceptual understanding, it is recommended to consult textbooks on atomic physics and quantum mechanics, as they typically cover this topic comprehensively. Additionally, there are numerous educational videos available on YouTube that can provide visual explanations and further insights. Engaging with both written and visual resources can enhance comprehension of the complexities involved in L-S interaction. Mastery of this topic is essential for deeper studies in quantum mechanics and atomic structure.