The Longest Day is, before the movie, a book by irish writer Cornelius Ryan about the invasion of Normandy in June 6, 1994, D-Day.

The book is a compelling collection of stories from survivors, civilians and official records, as well as personal experience from Ryan, who was a war correspondent on D-Day and actually saw the invasion first hand. He covered the II World War for Reuters and the London Daily Telegraph, from 1941 until the fall of Berlin in 1945.

It's a particularly touching book because of the horrible reality of the stories and the first person approach. We get to read about a parachuter stuck in the mud, drowning. Then we hear about a soldier getting sick on the boat and getting shot by the weak - but still deadly - German defenses.

The book is also very balanced, it tells equally the stories of the allied side and the German side, either on the high ranks or with the point of view of common soldiers. The story of the french civilians is sometimes incredible, it made me wish the book was illustrated with pictures of the least violent scenes described.

The book was first published in 1959 and it has been reprinted several times. Cornelius Ryan took a few years to collect all the data and interview people in the USA and Europe. In 1995, the Ohio University made an exhibition of his work, including notes and pictures.