The first of the books to be published will feature The Famous Five
Some of Enid Blyton's most popular characters will make a return in a set of 20 new books, her estate has said.
The Famous Five, The Faraway Tree and Malory Towers will all feature in the books to be released over two years.
Chorion, which owns the rights to the characters, said the books would "remain true to Blyton's classic storytelling style and values".
In the first, The Famous Five's Survival Guide, they try to solve The Mystery of the Royal Dragon of Siam.
Chorion said the book would be "packed full of stolen treasure, problem-solving, traps and traitors".
In September, The Faraway Tree will return for the first time since 1951.
New stories from The Wishing-Chair, Malory Towers and The Secret Series books will be available in 2009.
'Joy to millions'
Jeff Norton, of Chorion, said: "Blyton's stories have been enjoyed by millions over the years and there is a huge demand for more of her magical storytelling.
"Blyton was passionate in her advocacy of child literacy and as the guardians of her estate we see it as our duty to continue that legacy.
"By creating new stories that capture Blyton's values of imagination, wonder, thrills and happy endings, we hope to complement her original and ongoing titles and bring joy to millions more children in the years to come."
On Tuesday, Blyton beat Roald Dahl and JK Rowling to be named the UK's best-loved writer in a poll of 2,000 people.
Blyton, who died in 1968, wrote 700 stories over 40 years and has sold more than 500 million books worldwide.