A bible, actually. But ... on page 154, about Boisson, I read: In general, we need to drink 1.5 liters a day. [...] Which must be added ONE LITRE WATER ADDITIONAL PER KILOMETRE RUN. Which would mean ... FORTY-TWO-LITRE for a marathon! It is probably a translation error or confusion in the systems of measuring capacity or distance, but still! I sent a message to the editor MARABOUT about it. Wait and see ...