Foundation Model Post-Training. Methods, Systems, and Industrial Practice - Wei Sun

This book offers a systematic guide to post-training modern foundation models and turning them into reliable, deployable, and governable industrial systems. Rather than treating fine-tuning as a narrow algorithmic procedure, it presents post-training as a broad engineering discipline that includes model selection, supervised fine-tuning, preference optimization, reinforcement fine-tuning, tool use, retrieval augmentation, multimodal adaptation, evaluation, inference deployment, safety controls, and lifecycle governance.

The book begins by explaining the foundations of modern foundation models, including dense and mixture-of-experts architectures, reasoning models, multimodality, structured outputs, tool use, and the economic constraints that shape real-world model adoption. It then introduces the major post-training methods, comparing when supervised fine-tuning is sufficient, when preference optimization is appropriate, and when reinforcement fine-tuning becomes necessary for reasoning-heavy or verifiable tasks.

A major emphasis is placed on data and evaluation. The book discusses data collection, licensing, governance, cleaning, deduplication, synthetic data, preference data, reward data, safety data, judge-model evaluation, benchmark design, regression testing, and continuous model lifecycle management. It argues that post-training quality depends as much on data pipelines and evaluation gates as on training algorithms.

The systems section connects training choices with deployment realities, covering hardware planning, distributed training, inference serving, KV cache engineering, latency, throughput, observability, reliability, cost optimization, private deployment, edge deployment, and production operations. The book then applies these concepts across enterprise knowledge systems, software engineering agents, finance, healthcare, law, retail, manufacturing, and education.

The final part addresses safety, alignment, guardrails, red teaming, misuse prevention, compliance engineering, auditability, licensing, copyright, data provenance, and future directions such as reasoning agents, memory, world models, and continual post-training.

Designed for engineers, researchers, technical leaders, and governance professionals, this book provides a durable framework for understanding how foundation models become useful, safe, cost-aware, and accountable production systems.