The John Jay Knox Letters consist of twenty-four incoming items and one outgoing, reflecting the esteem with which Knox was held for his understanding of the country's financial crisis among economists, journalists, and politicians.

The Correspondence includes a number of speaking invitations (Henry Chandler Bowen, George Schneider, James Sturges, Horace White), and a letter from Abram S. Hewitt in which he reluctantly declines to hear Knox address the Commonwealth Club. White's invitation to address the Political Economy Club dinner includes a request for a copy of Knox's proposal for the rehabilitation of the national banking system. A letter from H. M. Alexander thanks Knox for a copy of his Pittsburgh address and promises to vote for him if he runs for comptroller of the currency.

Several items of correspondence request articles by Knox elucidating his position with regard to overhauling the national banking system and establishing gold, rather than silver, as the unit of measurement of the currency. H. C. Bowen asks Knox to contribute to a series of articles to be run in The Independent on the silver question, while Lorettus S. Metcalf requests an article for Forum on the banking system. Also, William B. Dana agrees to publish Knox "communication" in The Commercial & Financial Chronicle. Responding to the article which appeared in The Independent, Richard Rogers Bowker wrote:

I have looked over it with interest, and am, of course, inclined to trust your experienced judgment in matters connected with financiering. But it is always the case that it is not putting the money in but getting the money out of banks that makes the difficulty, as you yourself point out, and my own notion is that the danger from such a fiscal policy comes when danger should be carefully avoided.

In addition there is considerable correspondence regarding the then recently deceased Secretary of the Treasury William Windom (Philetus Sawyer, John Aikman Stewart, George Wilson). In a letter to Jay Gould, Knox wrote:

I have the pleasure of informing you that the subscriptions for the benefit of the wife of the late Secretary of the Treasury have been paid and the fund transmitted with a book containing the names of the donors to Mrs. Ellen T. Windom.

I have received this morning a letter from her acknowledging the receipt of my check for $53,000 in which she says "that I accept the testimonial with a degree of gratitude which I cannot express, and am deeply moved by the generosity of the gentlemen whose names accompany the check."

A letter from George Wilson requests that Knox deliver a eulogy for Windom before the Chamber of Commerce of the State of New York.

A letter from Francis Marion Burdick requests Knox to advise the Cornell University Senate concerning the suitability of James Laurence Laughlin for appointment to a chair in political economy, and a letter from Laughlin offers Knox assistance concerning various state histories.