The times may be a-changin', but one staple of life is immutable: the grandparents. They still come in every shape and size and each still has one thing in common -- an inviting, read-to-me lap.

What has been uncommon until recently in the dearth of books for children about this remarkable breed of human. The books described below, whether delivered with a hug or with a postage stamp, will help preserve and strengthen the unique bond between grandparent and grandchild. Ages 3-6

"Albert's Toothache." By Barbara Williams. Illustrated by Kay Chorao. (Dutton, $1.95).

No one believes that poor, toothless Albert Turtle has a toothache. No one, that is, except his perceptive grandmother, who discovers that Albert's "toothache" is the ache, resulting from the teeth of a gopher who bit his toe.

"Grandma Zoo" By Shirley Gordon. Pictures by Whitney Darrow Jr. (Harper and Row, $6.95).

Grandma's realistic animal sounds captivate her grandson during frequent long-distance telephone conversations. Their far-away love grows closer when grandma visits and actually brings along her "zoo."

"Great Grandfather, The Baby and Me." By Howard Knotts, (Atheneum, $5.95).

Great-grandfather relates how he once traveled by horseback for miles across a deserted prairie just to see a newborn baby. His tale eases his grandson's apprehensions and helps him look forward to the impending homecoming of his new sibling.

"Tell Me Grandma, Tell Me, Grandpa." By Shirlee P. Newman. Pictures by Joan Drescher. (Houghton Mifflin, $6.95).

Grandchildren seem to delight in hearing every detail of the evolution of their parents from babyhood to adulthood. In this warmly illustrated book, the curious grandchild turns her lively imagination loose as Grandma and Grandpa relate some family history. Ages 5-8

"The Two of Them." By Aliki. (Greenwillow, $7.95).

Her grandfather loved her from the day she was born. He showered her with understanding, love and affection even after he became bedridden, when their roles reversed. She will always remember the love they shared. Aliki's exquisite paintings and tender words make this a love story to treasure.

"My Island Grandma." By Kathryn Lasky. Illustrated by Emily McCully. Frederick Warne, $7.95).

Leaving the city behind, Abbey travels with her parents to a rugged island off Maine where her grandma lives. All summer she sails, swims, picks blueberries and lots more with her unique "Island Grandma." McCully's realistic reunderings will delight nature lovers.

"Timothy and Gramps." By Ron Brooks. (Bradbury Press, $6.95).

At school Timothy was quite and shy. At home with gramps he was lively and imaginative. Gramp's surprise visit to school during Show-and-Tell helps Timothy discover and take pride in his own unique self.

"A Mitzvah Is Something Special." By Phyllis Rose Eisenberg. Illustrated by Susan Jeschke. (Harper and Row, $6.95).

Two grandmothers will never forget the Mitzvah Lisa gives them. Neither will readers, young or otherwise. Ages 8-12

"There's a Rainbow in My Closet." by Patti Stren. (Harper and Row, $8.95).

Emma dreads the coming of gramma to take care of her while mom is out of town on business. After all, her friend Edgar warned her that "Grammas has blue-tinted hair and cook all the time." But Emma is in for a delightful surprise -- and a memorable visit.

"Felita." By Nicholasa Mobr. Pictures by Ray Cruz. (Dial Press, $6.95).

Felita halted to leave her close-knit and bustling ethnic neighborhood for what her parents felt was a better environment. Her grandmother, Abuelita, sensitively helps Felita make the difficult adjustment by stressing pride in her self and her heritage.

"Carnival and Kopeck and More About Hannah." By Mindy Warshaw Skoisky. Illustrated by Karen Ann Weinhaus. (Harper and Row, $7.95).

When Hannah breaks her promise to behave like a mensch, grandma sends her directly home from the carnival. Hannah realizes that living near someone you love means that "you get mad, you get sorry and you get glad." Sometimes over and over again.

"Freddy My Grandfather." By Nola Langner. (Four Winds, $6.95).

This vivacious granddaughter tries hard to explain why she's so lucky to have her grandfather, Freddy, living at her house. He shares the special treasures in his room. He tells tales about when he was a boy. He also speaks Hungarian with her mother and a "different" English to her. She always knows what he means though . . . he means the world to her.