CLEAN : Rare Turing notebook sells for $1m in New York

The video covers an auction featuring Alan Turing's composition notebook and an Enigma machine. The auction is significant as it includes the only known extensive manuscript by Turing, consisting of 56 pages on mathematics and computer science. This is the first time such a document has been sold, highlighting its rarity and historical importance.

Why is the manuscript considered rare according to the text?

What does the text imply about the value of handwritten documents by Alan Turing?