The biggest problem with collaboration is that it makes what Mr Newport calls “deep work” difficult, if not impossible. Deep work is the killer app of the knowledge economy: it is only by concentrating intensely that you can master a difficult discipline or solve a demanding problem. Many of the most productive knowledge workers go out of their way to avoid meetings and unplug electronic distractions. Peter Drucker, a management thinker, argued that you can do real work or go to meetings but you cannot do both. Jonathan Franzen, an author, unplugs from the internet when he is writing. Donald Knuth, a computer scientist, refuses to use e-mail on the ground that his job is to be “on the bottom of things” rather than “on top of things”. Richard Feynman, a legendary physicist, extolled the virtues of “active irresponsibility” when it came to taking part in academic meetings.