British soldiers liberated the camp only weeks later. They found 60,000 emaciated prisoners.
Otto Frank's mother wrote to her son, saying she was with him in his unspeakable sorrow.
"I don't want to & can't write about any details today.... Maybe some day later, I'll be able to ask everything I want to know..."
'It's not a sad book'
Elias says everyone in his family loved to write. Poems. Letters. Anything.
"That's where Anne got it from. She inherited it," Gerti Elias says.
It's the exchanges with Anne's family that are most poignant but the book that was published provides insight into the lives of others linked by blood.
How Otto Frank's father died at such a young age and the irony of how he and his brothers fought for the Fatherland in World War I.
Some of the letters from the attic were revelations for Elias when he finally read through everything. He hadn't known what a counselor Otto Frank had been to his mother, Leni. How he gave her advice on how to behave with men.
"It's not a sad book," Elias says.
In America, he hopes to convey the richness of his family's lives before the Nazis rose to power. In his voice, he hopes his audiences will again hear Anne, as she was as a free-spirited girl, before she was silenced.