01
AI Foundations
Understand what AI is, how systems learn, where they fail, and how to judge claims without hype.
Free AI library
Learn AI.Free forever.
1019 plain-English guides, structured learning paths, and an open library — built by an independent 501(c)(3) nonprofit so anyone can understand modern AI.
1019Free guides
9Topic tracks
~2 minPer guide
~34hReading time
Start here
Five outcome-based courses
Each course includes explicit outcomes, mapped competencies, practice activities, and an applied capstone.
02
Responsible AI User
Use AI productively while protecting privacy, checking outputs, and preserving human accountability.
03
AI at Work
Evaluate workplace use cases, run safe pilots, measure value, and communicate changes responsibly.
04
AI Policy & Society
Analyze AI systems through rights, equity, governance, safety, and public-interest outcomes.
05
Building with AI Systems
Understand language models, retrieval, agents, evaluation, cost, and deployment safeguards through practical system design.
Topic tracks
Browse by track
Jump into the area you care about. Every track has multiple plain-English guides.
FundamentalsCore concepts: how AI works at a high level.84 guides Language AILLMs, NLP, ChatGPT, prompting, and text understanding.155 guides Visual AIImage generation, computer vision, video, and design.133 guides Audio AIVoice, music, podcasting, and audio-first AI.117 guides CompaniesProfiles of OpenAI, Anthropic, Google, Meta, and more.121 guides ApplicationsHow AI shows up in coding, search, agents, and daily life.111 guides IndustriesAI in healthcare, finance, education, energy, and more.91 guides TechnicalChips, fine-tuning, RAG, vectors, and AI infrastructure.177 guides SocietyBias, privacy, copyright, safety, and the AI future.30 guides
Full library
All guides
1019 of 1019 guides shown. Filter by track or search above.
Language AI
BM25 and Lexical Retrieval
BM25 is the classic keyword-based ranking function that scores documents by how often query terms appear, adjusted for term rarity and document length.
Language AIHyDE Hypothetical Document Embeddings
HyDE improves retrieval by first asking a language model to imagine a fake answer document, then searching with that document's embedding instead of the raw…
ApplicationsAI in Voice Biometrics Authentication
Voice biometrics uses AI to verify your identity from the unique acoustic and behavioral patterns in your speech.
ApplicationsAI in Subtitling and Closed Captioning
AI turns spoken audio into synchronized on-screen text, automating subtitles for translation and closed captions for accessibility.
ApplicationsAI in Patent Search and Analysis
AI helps inventors, lawyers, and examiners search millions of patents and analyze them by meaning rather than just keywords.
Language AISpeculative Decoding Draft Models
Speculative decoding uses a small, fast 'draft' model to guess several upcoming tokens that a large model then verifies in one pass.
Language AILookahead Decoding
Lookahead decoding speeds up LLM generation without any extra draft model by guessing and verifying multiple future tokens in parallel using n-grams…
Language AIColBERT Late Interaction Retrieval
ColBERT is a retrieval model that represents each query and document as many token-level vectors and scores them with a fine-grained 'late interaction' step.
TechnicalVanishing and Exploding Gradients
When training deep networks, error signals shrink toward zero or blow up toward infinity as they travel backward through many layers.
TechnicalGradient Clipping
A simple, widely used safeguard that caps how large gradient updates can get during training.
TechnicalWeight Initialization
How you set a neural network's starting weights before training begins, which strongly shapes whether signals and gradients stay healthy through deep layers.
Visual AIPerceptual Loss and LPIPS
Perceptual loss measures how similar two images look to humans by comparing deep neural network features instead of raw pixels.
Finished reading? Prove it.
Check what you learned with topic quizzes, then explore our structured courses and current certification requirements. Core guides remain free to read.