She said she wanted readers to get to know Che Guevara just as he was.
Diary of a Combatant covers his three-year guerrilla campaign which resulted in the overthrow of then-president Gen Fulgencio Batista and brought Fidel Castro to power.
The publishers said Che Guevara, a doctor by training, had terrible handwriting and it had taken them unusually long to decipher it.
The diary covers the period from the landing on Cuban shores of the revolutionaries on board the yacht Granma on 2 December 1956 to 1 January 1959, when they ousted Gen Batista.
The diary shed light on "Che Guevara's impressions of Cuba, its culture, identity and political context", according to the publishers.
To view video of launch of new book in Havana see this link to BBC website