The notebook disappeared from the Royal Library in the 70's and has not been seen since.
KB has now reported the theft to the police and the notebook has been removed from the auction.
- This is one of the worst manuscript thefts in recent times, says Strindberg researcher Göran Söderström to DN.
The book contains names, addresses and drawings, written down between 1893 and 1895, when Strindberg was in Germany and Paris, among other places.
The notebook was supposed to have been auctioned off by the auction house Sotheby's on Tuesday.