To authenticate users by email and password using Passport, you can follow these steps:

1. Install Passport and its relevant strategies (like passport-local for email and password authentication).
2. Set up a login route that receives the user's email and password from the frontend.
3. Implement a verification process (using bcrypt for password hashing) to validate the user's credentials against the database.
4. Upon successful verification, create a session for the user to maintain their authentication status.

By integrating these steps within your application, Passport can efficiently authenticate users using their email and password.