One day last summer Doris McNeely Johnson, 39, a college instructor, took her three children outside and taught them to jump double dutch, demonstrating how to turn the ropes just right.

She takes play seriously.

That's why Johnson, a psychology instructor at the University of the District of Columbia, has written "Children's Toys and Books," a guide to choosing playthings for children of all ages. She wrote the book after searching in vain for such a guide to help her in buying toys for her children.

"We tend to trivialize play. But play is as important to a child as work is to adults," Johnson explained. "If parents would listen they could hear the type of learning which occurs when children play."

Her book, published last month by Charles Scribner & Sons Inc., includes chapters on toys for handicapped children, toy safety, making playthings and buying books, the section she calls "my favorite."

Johnson offers guidelines for choosing books, such as picking those that have won the American Library Association's Caldecott Award for "best illustrated," or the Newberry Award for "best children's literature." She lists all the recipients of these awards.

She also suggests "a sequence" for choosing books, so that children begin with picture books, progress through fairy tales, and then expand their reading to include fiction, biographies and other nonfiction.

Johnson said she and her husband, Myles, a program analyst at UDC, have always spent hours playing with their children: Anike, 6, Nia, 9, and Myles (Jay), 13.

The author readily rattles off practical tips on toys, obviously pleased to be asked.

"Heavily advertised toys are usually not as well-constructed as others . . . and are over-priced," she said. "Parents should balance toy selection, buying advertised toys and those which they think are good for the child. Buy toys that tie together psychological and physical development. Buy toys you can play with together."

As a child, she said, she remembers playing with "jacks . . . a doll house . . . paper dolls . . . puzzles."

"You get the same eye-hand coordination with jacks that you get with computer toys, but jacks cost $1.19," she noted. "Parents today seem to think a child needs packaged toys."

Johnson first thought about writing a toy guide nearly 13 years ago when her son was a baby. She said she "went out and bought what I thought were good toys of significant play value," and "wasted a lot of money and saw many of the toys break quickly."

Searching for books that would guide her toy shopping, she found that the "few that existed were written in the 1930s and 1940s. Most were written for teachers and professionals. There was nothing for parents and grandparents."

Much of the book's advice came from Johnson's own experience.

"Don't give a tiny rattle to a child." she said. "A baby has no reflexive control. They'll bang their heads . . . . You put a mobile over their bed and a music box nearby. You appeal to their eyes and ears . . . . Later, when they're 5 or 6 months old, buy a large, heavy rattle."

She prefers toys that prompt children "to make up dialogue. A couple of years ago I got the children a real Victorian doll house," she said. "Even Jay participates. He says, 'I'll show you girls how to organize this furniture.' You should hear the conversations."

Johnson initially published her toy-buying tips as a booklet, then signed a contract with Scribner. She said she was so busy during the 3 1/2 years it took to complete the current volume that she had little time to play.

"Children's Toys and Books" is sold at the Capital Children's Museum, 800 Third St. NW, and the Cheshire Cat Children's Book Store, 5512 Connecticut Ave. NW. It can also be ordered by writing Johnson at P.O. Box 55258, Fort Washington, Md.