As a scholar, she works on the art and visual culture of the nineteenth and twentieth centuries, with a focus on the historical avant-garde, in particular Dada and Surrealism.
She has written on Diego Velázquez, Francisco Goya, Hugo Ball, Antonin Artaud, Lee Miller, Man Ray, Marcel Duchamp and others.
Leppanen graduated from the International Baccalaureate program at Lincoln Park High School in 1988.
[6] Leppanen co-edited with Dickran Tashjian and contributed two essays for the multi-media publication Joseph Cornell's Manual of Marvels (Thames & Hudson Press, 2012).
The project includes a volume of scholarly essays (by Dickran Tashjian, Dawn Ades, and Leppanen-Guerra), partial facsimile, and interactive CD-ROM digitally reproducing the pages of the book along with commentary – all packed in a wood-grain box.