Rated 5 out of 5 stars

It to be very good ad-on, however, since mid of February it does not synchronise any more.

EDIT: After recreating the address book as described below by Philippe it works again. Thank you for your help. Now six stars again.

This review is for a previous version of the add-on (56.7). 

may you contact me by email : cardbook (at) cardbook.icu

Edit : try to recreate your Google address book into CardBook (right click on your current address book, "New Address Book", then second entry "Remote", then second entry "Google", then enter your email address, Click on validate, click OK to the two consent screens, then Next many times... once it's done, remove your old CardBook address book...

Edit : for the consent screen, follow the Google instructions, and finally click on the Authorize button, CardBook will close this window when the code is received so do not close this window on your own ;)