There is no muse like the Seuss.

An unfinished manuscript by late children’s author Dr. Seuss is the basis for Dr. Seuss’s Horse Museum, due out September 3. According to Random House Children’s Books, illustrator Andrew Joyner finished the text, which features equine artwork by such notable artists as Pablo Picasso and Jackson Pollock, and will include cameo appearances by Seuss favorites the Grinch and the Cat in the Hat.

The collaborative book is described as being “both subtly Seussian and wholly [Joyner’s] own.”

Joyner’s previous credits include, Too Many Elephants in This House and The Swap.

Theodor Geisel, far more widely recognized as Dr. Seuss, died in 1991. Another posthumous release, from 2015, What Pet Should I Get, was a bestseller.