I have previously used the metric system. I still do in this book. But I also provide equivalent quantities in ounces, pints, etc., for the benefit of all those readers who have not yet metricized their kitchens. The equivalents given in the recipes are in round figures, which in my view are quite close enough. Thus, either 25 or 30 grams will be given as 1 ounce, the true equivalent to which is 28 grams.
I have ignored the difference between teaspoons and tablespoons of various nationalities, and assure readers that they may safely do likewise. The same applies to the cup, a measure which I find very convenient for certain things. The American cup is smaller than the British cup. The difference could be significant in certain contexts, but in those where I have used the cup it is not.