# Foundations

> Free resources, with credit to the original creators.

## Resources
- [The Illustrated Transformer](/foundations/llm-fundamentals/jay-alammar-the-illustrated-transformer/index.md): See how attention and encoder-decoder blocks fit together. (beginner; West; closed resource; by Jay Alammar)
- [Neural Networks: Zero to Hero](/foundations/courses-and-learning-paths/andrej-karpathy-neural-networks-zero-to-hero/index.md): Learn neural networks by implementing them in Python. (intermediate; West; closed resource; by Andrej Karpathy)
- [Hugging Face LLM Course](/foundations/courses-and-learning-paths/hugging-face-hugging-face-llm-course/index.md): A structured route through the Hugging Face ecosystem. (intermediate; other; open resource; by Hugging Face)
- [LLMs-from-scratch (book code)](/foundations/from-scratch-implementations/sebastian-raschka-llms-from-scratch/index.md): Follow a GPT implementation rather than treating the model as a black box. (intermediate; West; closed resource; by Sebastian Raschka)
- [Applied LLMs: What We've Learned From A Year of Building with LLMs](/foundations/practitioner-overviews/yan-bischof-frye-husain-liu-shankar-applied-llms-what-we-ve-learned-from-a-year-of-building-with-llms/index.md): Cross-functional lessons from building language-model applications. (intermediate; West; closed resource; by Yan, Bischof, Frye, Husain, Liu, Shankar)
- [Lil'Log](/foundations/practitioner-overviews/lilian-weng-lil-log/index.md): Research learning notes that connect methods to their literature. (advanced; West; closed resource; by Lilian Weng)