In her 40-year career, Ana Maria Machado has had more than 100 books published in Brazil and in translation in over 18 countries, with more than eighteen million copies sold. She has received numerous awards for her work, most notably the Hans Christian Andersen Award in 2000 for her life's work, the highest honour in children's literature. Ana worked as a journalist for Elle magazine in Paris and the BBC in London, as well as becoming a professor at the Sorbonne. Ana never stopped writing children's stories throughout this period. In 1979, she opened the Bookstore Malasartes, the first children's bookstore in Brazil, with the aim of ¿¿providing a space for children to find and read good books. In 2001, the Brazilian Academy of Letters gave her the greatest national literary award, the Machado de Assis, for her achievements. In 2003, Ana Maria was elected chair of the Brazilian Academy of Letters, replacing Dr. Evandro Lins e Silva. For the first time, an author with a significant proportion of work for children had been chosen for the Academy. Ana Maria Machado lives with her family in Rio de Janeiro.

Sonia, Pedro and their classmates are baffled. Mysterious messages keep popping up on their computers, on their mobile phones, on websites they visit, even on a radio programme they listen to. It is a voice from the past - but who is trying to contact them from out of history, and why? Follow the clues from their school in modern-day Brazil through the ages to ancient Egypt, to a medieval wizard's castle laboratory and to the ships that sailed from Europe to discover the New World. Can you solve the History Mystery?