In order to login to MIT Textbooks, you must have your personal certificates installed in your browser. You can also use all of the site without logging in.
To install your certificates, visit the Certificates at MIT page on the IS&T Knowledge Base. To verify you have installed them correctly, use the Certificate Test Page.
If you are seeing this message and have already installed your certificates, it's possible that you clicked 'Cancel' when your browser requested which certificate to present. If this is the case, you will have to restart your browser before it will prompt you to login again.
Textbooks