Last update 4 November 2021.
I love reading academic studies of the romance genre. One of the most accessible is Dangerous Men and Adventurous Women: Romance Writers on the Appeal of the Romance.
A Natural History of the Romance Novel offers useful ways to look at the structure of romance novels.
The Woman’s Historical Novel: British Women Writers, 1900-2000 doesn’t go into genre Romance, but offers some useful historical background and critique.
Empowerment versus Oppression: Twenty First Century Views of Popular Romance Novels features essays on various Romance sub-genres.