I've been binge reading the Lupin books and I've got absolutely hooked on each one, despite them not being the usual genre of books I read. While I appreciated that Lupin was a more prominent character in this than in “The Hollow Needle”, I was not a fan of the ending.

Lupin losing his will to live was sudden, and though understandable, the fact that he enrolled in the war was a biiiiiit too much for me

. Nevertheless, a thrilling and enjoyable read.