The manga Uzumaki, which the movie is based upon, was written by Ito Junji. In Japan, the story was serialized in Weekly Big Spirits, a horror comic book. In North America, it is published by Viz as a set of three graphic novels. English translation was provided by Oniki Yuji. (Please note, I write names last first here.)
The first book contains chapters 1 through 6. The second holds chapters 7 through 12. The third, chapters 13 through 19, as well as a bonus "lost" chapter. Each book opens with two or so color pages introducing the book (and also opening the first chapter of the book); each book ends with a comic afterword starring the artist himself.
Uzumaki was nominated for a 2002 Eisner Award. As far as I'm concerned, it is certainly worthy, and one of the best works of horror I've read.
I have a list of chapter names now, that I'd like to share with you all.
Book 1:
Chapter 1: The Spiral Obsession, pt. 1
Chapter 2: The Spiral Obesession, pt. 2
Chapter 3: The Scar
Chapter 4: The Firing Effect
Chapter 5: Twisted Souls
Chapter 6: Medusa
Book 2:
Chapter 7: Jack-In-The-Box
Chapter 8: The Snail
Chapter 9: The Black Lighthouse
Chapter 10: Mosquitoes
Chapter 11: The Umbilical Cord
Chapter 12: The Storm
Book 3:
Chapter 13: The House
Chapter 14: Butterflies
Chapter 15: Chaos
Chapter 16: Erosion
Chapter 17: Escape
Chapter 18: The Labyrinth
Chapter 19: Completion
Lost Chapter: Galaxies