Base, Instruct, and Think LLMs: What's the Difference?

When I was trying to learn more about LLMs, I found terms like pre-training, post-training, base model, instruction following, and reasoning really confusing. I didn’t understand what a base model was or why it needed post-training. In this article, I aim to help readers build an intuitive understanding of base models, instruction-tuned models, and thinking models through several practical…