The Lake Harriet elf has been inspiring kids of all ages to believe in a world they can't see for 22 years. Now Mr. Little Guy has inspired something more tangible -- a young adult adventure novel.

"Lylian/Lost Land of the Lytles" springs from the pen of the spokesman for the denizen of the green ash with the small door on the south shore of Harriet. It's where nearly a generation of children have left messages and eagerly awaited responses.

The locally self-published book offers a back story for the elf. It's the brainchild of Thomas Sandberg, a Minneapolis native and Roosevelt alum who owns a creative company in the warehouse district.

It's his maiden effort at fiction but as he put it, "making things up is what I do for a living." His aim was to create another magical land in the tradition of Narnia or Middle Earth, building on a lifetime of reading fantasy and science fiction books.

As for the elf, Sandbeg said, "I've often wondered where he came from." His interpretation touches on themes of the importance of belief, boldness and friendship.

The identity of the the Harriet elf has long been guarded, and the elf is not ready to come out of that closet. Let's just say that Sandberg is a close personal friend.

"Everyone has their own idea of who the elf is and what the elf does in his down time, when he's not answering letters, and this is my interpretation."

The plot traces the ventures of Lucia, a Minneapolis girl with a bent for offbeat inventions as she is unexpectedly invited to the forbidden island of Lylian after inventing a serum. It's a voyage of self-discovery and danger for her, involving a scheming villain, bumbling henchmen, saddled cats, Lytles who favor pirate-derived garb, and of course, the little people.

The book jacket even depicts a topographic map of Lylian Island. That's a leftover from Sandberg's original concept, which was a travel guide about the mythical mid-Atlantic isle in the style of Frommer or Lonely Planet. He tossed that.

He labored on that and its more fictive successor off and on for seven years. "I knew the first page of the of the book and the last page of it," he said. The real work came in between. The first draft took six months, but it was revised through three or four major iterations under the guidance of editors he trusts.

Sharp-eyed fans may recognize the setting for the cover illustration, a photo featuring a saddled cat (not photoshopped). It's set on the wall surrounding Sandberg's architecturally distinguished 1915 house in the King Field neighborhood.

Sandberg will hold a book release reading and signing at Wild Rumpus bookstore, 2720 W. 43rd St., on Wednesday from 6-8 p.m. The book is available there, from Amazon or through www.lylianisland.com

(Above: The elf abode at Lake Harriet. Staff photo by Carlos Gonzalez)