Artificial Intelligence (AI), and specifically Large Language Models (LLMs) such as GPT-4 from OpenAI, is taking over the software development world - more and more applications are trying to build integrations with those powerful models. But how do those models work? Is their power as unlimited as it seems? How to communicate with AI and make sure it does what you need? In this talk, you will get a practical introduction to the world of LLMs and the art and science of prompt crafting. You will learn how to use AI models, how to design efficient inputs to the model - called prompts - and what techniques you can use to make your prompts better or how to chain multiple AI queries together. I will also discuss what are UX considerations when building AI tools and how to measure the impact of changes in AI systems... and try to answer the question - "should I integrate AI into my application?"