The Prestons studied at the University of Oxford, reading History and English respectively. Both are keen travellers and have visited more than 140 countries.
Their greatest love is India. Their research into the building of the Taj Mahal led them to explore the early history of the dynasty which built it – the Mughal Empire. They have read all the chronicles of the Mughal period in order to understand the history of the founders of the Mughal dynasty for their fiction work Empire of the Moghul. Over the years they have also retraced the steps of the Mughals from the Ferghana Valley in Kyrgyzstan – home to the first Moghul emperor, the boy-king Babur – to Iran and to the blue domes and minarets of Samarkand in Uzbekistan, across the red deserts to the Oxus River, over the Hindu Kush to Kabul and Afghanistan and down through the Khyber Pass to the plains of northern India. Empire of the Moghul consists of six books which is about the epic rise and fall of one of the world’s most powerful, opulent, and glamorous dynasties across 200 years. 
Until the series they had done only serious non-fiction, and it was their first attempt at historical fiction. They decided to create a new persona to make a distinction between their earlier writing and this new series. "Rutherford" came from the Nobel Laureate Ernest Rutherford, and Alex was chosen as a name that could be male or female.
Books by Diana and Michael Preston under the pseudonym "Alex Rutherford"
- Empire of the Moghul : Raiders from the North
- Empire of the Moghul : Brothers at War
- Empire of the Moghul : Ruler of the World
- Empire of the Moghul : The Tainted Throne
- Empire of the Moghul : The Serpent's Tooth
- Empire of the Moghul : Traitors in the Shadows
- A Pirate of Exquisite Mind: Explorer, Naturalist, and Buccaneer: The Life of William Dampier
- Taj Mahal: Passion and Genius at the Heart of the Moghul Empire
- A Teardrop on the Cheek of Time: The Story of the Taj Mahal
- "Alex Rutherford". Macmillan Publishers.
- "Alex Rutherford". Goodreads.
- "Empire of the Moghul". Macmillan Publishers.
- "Interview : Diana Preston". The Hindu.
- Raiders from the North written by Alex Rutherford
- Empire of the Moghul: Ruler of the World by Alex Rutherford | Review | Historical Novels Review
- Book review: 'Empire of The Moghul: The Tainted Throne' | Latest News & Updates at Daily News & Analysis
- Books | Alex Rutherford | Reviews | Time Out Mumbai