The document discusses research into analyzing the eigenvalue spectrum distribution (ESD) of deep neural network layer weight matrices. It is proposed that well-trained networks exhibit "heavy-tailed self-regularization" where the ESD follows a heavy-tailed distribution like a power law. A tool called WeightWatcher is introduced that analyzes layer quality by fitting the ESD to theoretical heavy-tailed distributions inspired by random matrix theory and neuroscience. WeightWatcher can detect overfitting and help accelerate training by adjusting layer learning rates.