Disclaimer: I received a free review copy of this book. The book links are affiliate links; I get a small amount from any purchase you make through them. Grok is a Python web framework, built on top of the Zope Toolkit, which is the core of what used to be called Zope 3 and is now rebranded as BlueBream. Confused yet? Get used to it: the small pluggable components are the heart and soul of ZTK, and the source of its flexibility.