Here's a nice article that discusses the historical importance of the letter and the problem Goedel raises: https://ecommons.cornell.edu/bitstream/handle/1813/

Here's a nice article that discusses the historical importance of the letter and the problem Goedel raises: https://ecommons.cornell.edu/bitstream/handle/1813/6910/89-994.pdf?sequence=1 https://ecommons.cornell.edu/bitstream/handle/1813/6910/89-9...