Yep. The book was written 20 years after ‘Christmas’ was released and then became a TV special in 1978.
The prequel, ‘Halloween is Grinch Night,’ is set years before ‘Christmas’ and ol’ Grinch is going to terrorize the citizens of Whoville. This time though a kid named Euchariah is the one to ruin his plans.
The TV special earned itself 1978 Primetime Emmy Award for Outstanding Children’s Program. So it was well received even if most of us don’t know about it. In any case you can watch it below, even if it’s Christmas time.