Sir

In your News Feature (Nature 415, 257; 2002), you suggest that the Habilitation postdoctoral thesis is “unique to German-speaking countries”. Sadly, not so. L'habilitation à diriger des recherches is alive and kicking and France, and is an obligation for anyone who supervises a PhD student. Although not usually as large as its German equivalent (mine was only 15,000 words long), the rules governing its size are effectively determined by each faculty. There is a tendency for it to creep up to the size of the old thèse d'état, usually more than 100,000 words long, which it was designed to replace in 1988.