A must guide not to panic

Ah, that is it does not write to the Guide ... Years after writing the adventures of Arthur Dent are a great example of humorous SF, and the many derivatives (soon the movie?) Prove worldwide success of this essential bedtime reading. Rest of France where too few people still understand the reference when launching a "Do not Panic!"
Read in English, of course, because of British humor, it is savored like that.