ONNX has emerged as the de facto standard for deploying portable, framework-agnostic machine learning models across diverse hardware platforms. Ultimate ONNX for Deep Learning Optimization provides a structured, end-to-end guide to the ONNX ecosystem, starting with ONNX fundamentals, model representation, and framework integration. You will learn how to export models from PyTorch, TensorFlow, and Scikit-Learn, inspect and modify ONNX graphs, and leverage ONNX Runtime and ONNX Simplifier for inference optimization. Each chapter builds technical depth, equipping you with the tools required to move models beyond experimentation. The book focuses on performance-critical optimization techniques, including quantization, pruning, and knowledge distillation, followed by practical deployment on edge devices such as Raspberry Pi. Through complete, real-world case studies covering object detection, speech recognition, and compact language models, you can implement custom operators, follow deployment best practices, and understand production constraints. Thus, by the end of this book, you will be capable of designing, optimizing, and deploying efficient ONNX-based AI systems for edge environments.