The primary scope of this book is to communicate the current state of the art of large language model applications in the domain of information retrieval and search with a pragmatic perspective on industrial adoption via open source software. To this end, the book is organised in three parts: "Large Language Models" gives an introduction to artificial intelligence and large language models, including an overview of open source and commercial options. Next, "Large Language Models and Search" describes techniques and strategies to integrate large language models in search projects, including how to choose the right model for a specific use case and how to avoid the classic mistakes that can happen in the process. Eventually, "How to Use Open Source Software to Interact with Large Language Mo
