His second book, Sundown (1934) is his most well known, an exploration of the disruption of the people and their society at the time of the oil boom, which also attracted criminal activities by leading whites in the county and state, including murder of Osage.

His third book, Talking to the Moon (1945), has been compared to Henry David Thoreau's Walden and was written while living at The Blackjacks.

The Blackjacks in the Osage Hills, where he did much of his writing, was acquired in 2014 by the Nature Conservancy of Oklahoma to be incorporated into the Tallgrass Prairie Preserve.

[12] In the summer of 1916 he participated in an archaeology expedition near Grove, Oklahoma alongside notable Oklahomans such as Joseph B. Thoburn, Elmer Fraker, and Lynn Riggs.

[20] He was admitted to Michaelmas term at Oxford University, but skipped his first semester to go big game hunting in the Rocky Mountains.

Their brief conversation greatly upset his wife and Mathews later claimed his first daughter was conceived trying to console her from the meeting.

[30] Mathews and his wife returned to the United States in November 1924, first staying at the Hotel Edgemere in East Orange, New Jersey.

The family summered in Cape Ann, Massachusetts before moving to Pasadena, California that fall via the Panama Canal.

[35] He returned to Pasadena in February 1929, telling his wife he was not coming back and began selling his land investments in California.

[36] In April 1929, while living in the University Club of Los Angeles, he wrote his first piece for Sooner Magazine, "Hunting the Red Deer of Scotland.

Historian Michael Snyder suggests that Mathews attempt to remove them from his biography was out of embarrassment of the failure of his first marriage and absence from his children's lives.

[40] In addition to Sooner Magazine, he started writing the "Our Osage Hills" column for the Pawhuska Journal-Capital between 1930 and 1931 and joined the Izaak Walton League.

[43] In January 1932, Thomas Gore arranged for Mathews to meet Herbert Hoover, to see if the president would write the introduction for his book.

[44] When the novel became a bestseller in January 1933, Walter Ferguson and his wife Lucia Loomis hosted a large celebration for Mathews in Tulsa at their home.

It is marked by its realism, as Mathews wanted to represent the Indian in a way that had not been recognized in European-American cultural stereotypes.

"[46] The semi-autobiographical work is about Challenge "Chal" Windzer, a young Osage man of mixed-blood ancestry.

[47] After leaving home to study at the University of Oklahoma and serve in the military, Chal feels estranged when he returns to his tribal community.

[49] Mathews was elected to the Osage Nation tribal council in June 1934 served two four year terms, representing the Progressive Party, during the tenure of Principal Chief Fred Lookout.

His tenure was not popular among the Fullblood Party, which argued the tribe overvalued Mathews's education and gave him too much power.

His work Talking to the Moon (1945) is a retrospective account of the ten years he spent in the "blackjacks" of his homeland, observing nature and reflecting on the influence of the environment on Osage culture.

Lee Schweninger noted that Mathews used irony to create distance between the narrator and himself as the subject of autobiographical reflection.

The two first met in 1908 when Marland came to bid at the "Million Dollar Elm" in Osage County, and ran in similar social circles.

[75] After brief talks with Oklahoma and Holt, Mathews submitted Life and Death of an Oilman: The Career of E. W. Marland in 1949 to Chicago and the book was published in October 1951.

[77] Based on years of collecting information from tribal elders through the oral tradition, in addition to conducting historical research, Mathews wrote The Osages: Children of the Middle Waters (1961).

[78] It has been described as "his magnum opus and a pioneering achievement for both its reliance on the oral tradition and presentation of a particular tribal history from an Indian point of view.

He helped lobby the entire Oklahoma Congressional Delegation to oppose the bill while staying with his younger sister Florence's husband Michael Feighan.

[82] Mathews died on June 11, 1979, in Pawhuska and was buried at his request in his garden near the cabin in the Osage Hills where he did much of his writing.

[84] In the 1960s Mathews wrote a number of short stories, some drawing from folk traditions of the Osage and other cultures, including Scotland.

Mathews told these stories from the point of view of bird and animal protagonists, an act of imagination that decenters human life.

The cabin and gravesite were acquired about 2014 by the Nature Conservancy of Oklahoma and added to its Tallgrass Prairie Preserve, which it administers.