This chapter introduces the foundational concepts essential to understanding and applying prompt engineering effectively. It begins with an overview of artificial intelligence (AI), its historical evolution, and the transformative impact of generative AI in various domains. The discussion highlights the pivotal role of natural language processing (NLP) in bridging human–computer communication, with a focus on large language models (LLMs) and their capabilities. Key topics include pre-training and fine-tuning, the distinctions between prompting AI and web searches, and the significance of crafting precise and context-aware prompts to optimise AI interactions. The chapter further explores prompt engineering techniques, patterns, and optimisation strategies, emphasising the importance of safety and ethical considerations. By synthesising these elements, this chapter lays the groundwork for leveraging prompt engineering as a critical skill for enhancing AI reliability and adaptability across diverse applications.