The book existed because critical post-training methods, such as rejection sampling, outcome reward models, and character training, had no foundational online material explaining them and still lack such resources today.

The book began as a website documenting post-training methods that had little to no foundational online material, like rejection sampling, outcome reward models, and character training, which helped make it popular as one of the few places covering these topics intuition-first. ✦ AI generated

Nathan Lambert · Interconnects · 2026-08-10 · original ↗

The book started as a website where I wanted to document key methods of post-training that had potentially no online material explaining them. If there was something, I couldn't find it. This existed for more topics than you would expect, given post-training was already popular in 2024 (when I bought the domain), and continues to this day. Topics like rejection sampling, outcome reward models, and character training are prime examples.

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