New book: The Indo-European language family
The Indo-European language family: A phylogenetic perspective has been published at Cambridge University Press with an open access licence. It can be downloaded for free here: https://doi.org/10.1017/9781108758666
The book has been edited by Thomas Olander and contains fifteen chapters by various authors on methodology and on the classification of the Indo-European language branches: Celtic, Germanic, Greek, Indo-Iranian etc. The book takes a phylogenetic perspective on the Indo-European language family and seeks to uncover the relationships among the separate branches as well as internally in the individual branches.
Thomas Olander has written a Twitter thread about the publication: https://twitter.com/2lander/status/1570687916149714945.