[1][3][4] Her research combines modern imaging with fossils to understand the evolution of life, in particular that of early fish, and in 2015 "rewrote" the vertebrate family tree.

[9][10] In 2017, Giles was awarded a Royal Society Dorothy Hodgkin Fellowship to study the evolution of the Actinopterygii, otherwise known as ray-finned fishes, which comprise more than half of all living vertebrates.

[13] Giles uses x-ray tomography to study the bone structure of Actinopterygii[1][13] and is one of the leading experts on the evolutionary relationships and adaptations of early fish.

[15][17][18] A foundational component of her work is the use of computed tomography (CT) scanning in order to study the internal anatomy of fossils[19][20][21][22] and to reconstruct the soft tissue structures that are not directly preserved.

[27] Giles' research has been published in leading scientific journals, including Nature,[14][16] eLife,[28] Current Biology,[29] and Proceedings of the Royal Society B[20] and has been covered by numerous media outlets.