Grandy is best known for her widely-praised trilogy The Seven Blue Mountains of Oz:
- Book 1 — The Disenchanted Princess of Oz (1995)
- Book 2 — Tippetarius in Oz (2000)
- Book 3 — Zim Greenleaf of Oz (2005).
In addition to writing the texts, Grandy also created most of the illustrations (Marcus Mebes and Luciano Vecchio contribute artwork to the trilogy's final volume). The second volume of the trilogy adapts and expands a Grandy short story titled "The Way to the Emerald City" that was printed in Oziana in 1983.
Grandy also wrote Forever in Oz (2006), and collaborated with Dulabone on the authorship of Thorns and Private Files in Oz (1998). Earlier, Grandy created the computer game Zim Greenleaf's Laboratory (1992).
As an illustrator, Grandy's pictures appear in a dozen books, other writers' works as well as her own. Her illustrated works include books by Phyllis Ann Karr, Dulabone's The Colorful Kitten of Oz (1990), and two multi-author and multi-illustrator projects, The Shifting Sands of Oz (1995) and Fwiirp in Oz (1996). She provided some pictures for Our Trip to Oz (1989) and The Enchanted Emeralds of Oz (1990), two books written and illustrated by a group of fourth-and-fifth-grade students, the Wiz Kids of Oz.