In this episode Dr Peter Bandettini and co-host Dr Brendan Ritchie interview Dr Grace Lindsay. They find out about her new book 'Models of the mind' and about the process of writing a book. In doing so, they consider different types of brain models, from simply descriptive to more mechanistic, from too simple to overfitted. They describe the challenge in neuroscience of network modelling - the many unknowns and limited data and how output of the model may help inform its accuracy. They then discuss specific models, such as Deep Neural Networks, and how this type of modelling may progress in the future. Last, Lindsay gives some thoughts about the future hopes, philosophies, and strategies of modelling - how doing it well is both an art and a science.