Rolf-Dieter Heuer - NYTimes.com The physicist Rolf-Dieter Heuer is director general of the European Council for Nuclear Research, or CERN, in Switzerland, where he oversees efforts to discover the subatomic underpinnings of the universe using the 17-mile Large Hadron Collider. READING E-mails, unfortunately. Most of it has to do with the management of CERN. My job compares to being a mayor of a small city of 3,000 inhabitants that houses several thousand tourists every day. When it comes to books, however, I enjoy biographies such as Boris Stoicheff on Gerhard Herzberg or Ronald Clark on Einstein. And I like intelligent crime stories. The rabbi series by Harry Kemelman is an example. The rabbi uses logic to solve crime. I like logic. I don't like things going on by chance. LISTENING If you come home in the evening and you are really tired, you have two choices. You can choose rock music, which wakes you up and then the next day you are tired again or you can take some music that calms you down and you can talk in parallel. I like Mozart. WATCHING I'm a big soccer fan, so I'm trying to keep up with the World Cup qualifiers. To some extent, the way you have success in soccer is the same as in particle physics. If you have 11 geniuses on the field, you will not win. The geniuses will fight against each other and there is no team. You need the right mixture of geniuses and workers. FOLLOWING I read a lot of newspapers online, and frequently find myself shocked by the comment threads that follow certain articles. I suppose I'm not the only one to worry about the long-term consequences of transferring our social interactions from face to face to online. It's so easy to do something anonymously. This is a danger. If you have an aggressive opinion, you should say who you are. COLLECTING I'm a great fan of traveling with old guidebooks. I have a "Plan de Paris par Arrondissement," first published in 1955, and it's interesting to see what's changed and what's not. It gives you an insight into how people used to travel. Being German, of course, I also have a healthy collection of Baedekers, and only wish I might one day find some of the early editions. I think the oldest guidebook in my collection is from 1901, London. EATING Sometimes a fondue is just the best thing in the evening. Don't ask me what kinds of cheese. I have to be very diplomatic. CERN is on the Swiss-French border. I like the Swiss cheese and I like the French cheese.