# Auth in Theory

- [Sessions](/sei-example/node-express/express-authentication/auth-in-theory/02sessions.md)
- [Passwords](/sei-example/node-express/express-authentication/auth-in-theory/03passwords.md)
- [Middleware](/sei-example/node-express/express-authentication/auth-in-theory/04middleware.md)
- [Hooks](/sei-example/node-express/express-authentication/auth-in-theory/05hooks.md)