Reddit reviews The Alchemical Body: Siddha Traditions in Medieval India

>anything modern on yoga or meditation

Depends, from both an academic and practice angle Georg Feuerstein is knowledgeable and insightful, worth reading;

>Historian of religions Mircea Eliade called Feuerstein's The Philosophy of Classical Yoga, "one of the most profound and original contributions to the understanding of classical yoga",

and other's, like David Gordon Whites work, such as The Alchemical Body: Siddha Traditions in Medieval India are relevant.

Desikachar, son of Krishnamacharya, who taught most of the teachers who brought contemporary yoga to the West, also published a book that is helpful for establishing and refining ones practice if exploring yoga as a way.