Free AI library

Fundamentals guidesFree forever.

84 plain-English guides, structured learning paths, and an open library — built by an independent 501(c)(3) nonprofit so anyone can understand modern AI.

84Free guides
1Topic tracks
~2 minPer guide
~3hReading time

Start here

Five outcome-based courses

Each course includes explicit outcomes, mapped competencies, practice activities, and an applied capstone.

Topic tracks

Browse by track

Jump into the area you care about. Every track has multiple plain-English guides.

Full library

All guides

84 of 1019 guides shown. Filter by track or search above.

Fundamentals

Self-Play Fine-Tuning

Self-play fine-tuning improves a model by having it compete against or learn from its own past outputs, generating its own training signal.

2 min readRead
Fundamentals

Test-Time Training

Test-time training (TTT) lets a model keep learning from each new input at the moment it makes a prediction, instead of staying frozen after training.

2 min readRead
Fundamentals

Grokking and Delayed Generalization

Grokking is a startling phenomenon where a neural network first memorizes its training data, sits at near-zero validation accuracy for a long time, and then…

2 min readRead
Fundamentals

Overfitting and Underfitting

Overfitting is when a model memorizes its training data and fails on new examples; underfitting is when it is too simple to capture the real pattern.

2 min readRead
Fundamentals

Regularization

Regularization is a set of techniques that deliberately constrain a model so it generalizes to new data instead of memorizing the training set.

2 min readRead
Fundamentals

Backpropagation

Backpropagation is the algorithm that lets a neural network learn from its mistakes by efficiently calculating how much each weight contributed to the error.

2 min readRead
Fundamentals

Gradient Descent

Gradient descent is the optimization method that actually moves a model's weights downhill toward lower error, one small step at a time.

2 min readRead
Fundamentals

Loss Functions

A loss function is the single number that tells a model how wrong its predictions are, turning a vague goal into something math can optimize.

2 min readRead
Fundamentals

Activation Functions

Activation functions are the small nonlinear gates inside each neuron that let neural networks learn complex, curved patterns instead of just straight lines.

2 min readRead
Fundamentals

Convolutional Neural Networks

Convolutional Neural Networks (CNNs) are the workhorse architecture for understanding images.

2 min readRead
Fundamentals

Recurrent Neural Networks

Recurrent Neural Networks (RNNs) are built to handle sequences like text, speech, and time series.

2 min readRead
Fundamentals

Generative Adversarial Networks

Generative Adversarial Networks (GANs) create realistic new data by pitting two neural networks against each other in a contest.

2 min readRead

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.