Epileptogenesis is the process by which parts of a normal brain are converted to a hyperexcitable brain, often after an injury. Researchers must understand this process before they know where and how to change it. Animal models are used to evaluate the process of epileptogenesis by studing status epelepticus, electrical kindling, or other methods that provoke injuries. All are associated with neuronal loss to more or less degree, synaptic reorganization, axon sprouting, neurogenesis, gliosis, and changes in gene expression in neurons and astrocytes. He describes several types of animal models and how they might be useful in developing effective strategies for preventing epilepsy.