What happens in our brain when we make a decision? What triggers a neuron to send out a signal? What is the neural code? This textbook for advanced undergraduate and beginning graduate students provides a thorough and up-to-date introduction to the fields of computational and theoretical neuroscience. It covers classical topics including the HodgkinHuxley equations and Hopfield model as well as modern developments in the field such as generalized linear models and decision theory. Concepts are i