Interesting, there appears to be a misprint in Practical Hints 6th ed. It says 1 Imperial pint (which is wrong) and 1.8 US Pints (which I believe to be what was intended). Also appears that Google Docs doesn't support PDF comments very well.
At any rate, I agree with the above. 'Book' capacity is 1.8 pints, but ignore that and fill until it is full.