The author wrote the novel 'Submarine' which I enjoyed as a film. This is a memoir of his efforts to understand the life of his great-grandfather, an eccentric scientist who had invented radioactive toothpaste... and who fled Nazi Germany.

Joe Dunthorne thought he knew his great-grandfather's story: Siegfried had in fact written a 2,000 page account of his life. While none of the family had actually read it, because it was so dull and detailed, the myth of the man had been passed down the generations. 

Intrigued by the snippets he'd been told, Joe decided to read Siegfried's manuscript. But it revealed that the family stories weren't entirely right.

Though Siegfried did indeed create radioactive toothpaste, he was also responsible for experimenting with chemical warfare, poison gas, for the Germans.

Siegfried said he was seeking to find something which would incapacitate the enemy soldiers not harm them. He considered resigning when he knew the real intent of his masters but was persuaded to continue in his work. Ultimately he did flee to Turkey and continued his investigations there. 

It's an unusual memoir. It's full of humour and wry commentary on the everyday occurrences and challenges in the author's research, visits and interviews. And what he finds out about his great-grandfather reveals an extraordinary life. But the book also raises some big questions. 'Can we ever understand where we come from? Is every family in the end a work of fiction? And even if we uncover the truth, are we able to live with it?' Fascinating.