AS A STRANGER approaches the door, the dog's paws skid across the hall floor, and he brakes as he barks in the unmistakable baritone of a retriever.
The dog who answers Colby Rodowsky's door is mostly black Labrador, not a golden retriever like Sandy, the star of Rodowsky's latest book, ''Dog Days.'' Still, he is barking and drooling and wagging at the same time, just like Sandy.
Rodowsky doesn't look anything like Dawn O'Day, the rather frumpy children's book author who owns Sandy in ''Dog Days.'' Still, she is quiet and a bit shy at first, just like O'Day.
And Rodowsky and O'Day have something else in common: They both write captivating novels for kids.
''Dog Days'' is Rodowsky's 11th book. Like several of her earlier works, it is set in Maryland. And like most of her books, it has been praised by critics, receiving a ''superior'' rating in the most recent ''Horn Book Guide to Children's and Young Adult Books.''
Unlike most of her books, though, ''Dog Days'' is geared to a young audience, ages 7 to 10. She usually writes for pre-teens or young adults, an age group that stretches from 12 to almost 20.
''If I were smart, I'd probably keep writing the younger books, because they sell better,'' Rodowsky said with a laugh. ''But I'm not that smart; I write what I feel like writing . . . I have to say I enjoy writing the young adults more.''
Rodowsky, 59, was sitting in the sun room of her Guilford home. It's definitely a home, not a mansion, with what must be the same kitchen with the same white porcelain sink it had when the Rodowskys moved in 26 years ago.
Back then, Rodowsky was too busy being a mother to write children's books. ''I wrote grocery lists,'' she said. She and her husband, Lawrence, who is a judge on the Maryland Court of Appeals, have six children -- five daughters and one son. When the youngest one started grade school, Rodowsky decided to return to college.
She had majored in English at the College of Notre Dame, so she returned there in the early 1970s to take a writing tutorial with one of her former professors, Sister Maura.
''The first day of the tutorial, she said, 'Next week come in with an outline for a book,' and it just turned out that what came into my mind was a children's book,'' Rodowsky said. ''Every Friday I would take in whatever I had written -- and boy, you write when you're the only one in the class.''
During that first tutorial, Rodowsky wrote a children's book that she tried to sell, but couldn't. During a second tutorial with Sister Maura, Rodowsky wrote ''What About Me?'' which was published in 1976. Her other books include ''Julie's Daughter,'' an American Library Association (ALA) Best Book for Young Adults; ''The Gathering Room,'' an ALA Notable Book; and ''Evy-Ivy-Over,'' ''Fitchett's Folly,'' ''H, My Name is Henley,'' ''Keeping Time,'' ''P.S. Write Soon,'' ''Summer's Worth of Shame'' and ''Sydney, Herself.''
''Dog Days,'' published last year by Farrar, Straus and Giroux, is the story of Rosie Riggs, a girl of about 9. Her potentially miserable summer is saved, she thinks, when Dawn O'Day and Sandy move in next door. Sandy the golden retriever is the star of ''Sandy the Super Dog,'' and ''Sandy's Great Adventure,'' which just happen to be Rosie's very favorite books.
Rosie and her friend Skinny-bones Scott are determined to befriend Sandy, hoping they'll be included in their hero's next thrilling adventure. Instead, all of their efforts are thwarted by Dawn O'Day. The author politely declines every request the girls make in their schemes to spend more time with Sandy.
One day, however, Sandy disappears, and the girls wind up playing lead roles in one of Sandy the Super Dog's adventures after all. The characters are easy to identify with, and the illustrations by Kathleen Collins Howell complement the engaging plot. It's a fun summertime read.
After ''Dog Days'' came out, Rodowsky finished her first picture book, ''Jenny and the Grand Old Great Aunts,'' which is to be published next spring by Bradbury Press. Her next book will be another young adult novel, tentatively titled ''Safe as Pockets.'' Right now she is working on the final revisions with Stephen Roxburgh, her longtime editor at Farrar, Straus and Giroux.
The main character is a 17-year-old girl, and the setting is Sea City, which is really Ocean City, Md. ''I write an awful lot about the Eastern Shore,'' she said. ''Growing up, I spent most of my summers visiting my grandmother on the Eastern Shore of Virginia.''
Rodowsky's family lived in Baltimore, then New York, then Washington, D.C., and she returned to Baltimore to attend college at Notre Dame. Asked where she grew up in Baltimore, Rodowsky hesitated.
''Right across the street,'' she said with a laugh. ''I didn't set out to buy the house across the street from where I grew up. In fact, I sort of thought I shouldn't at the time. When I tell people, they say, 'Only in Baltimore could that happen.' ''