As a student he worked on the problem of squaring the square.

His later career concentrated on graph theory. Among other achievements, he disproved Tait's conjecture using the construction known as Tutte's fragment.

*more, please, on W. T. Tutte's glorious career, but I've got to go to work*

- Brooks, R. L.; Smith, C. A. B.; Stone, A. H.; and Tutte, W. T. "The Dissection of Rectangles into Squares."
*Duke Math. J.*7, 312-340, 1940