If you’re using an Australian recipe book, watch out for the tablespoon, or your baking will turn out all wrong.
In the United States, a tablespoon is half a fluid ounce, 14.8ml. In Canada and the United Kingdom, the metric tablespoon is a nice even 15ml. Close enough, I suppose, unless you’re measuring something crucial. But if you’re measuring something crucial, a tablespoon probably isn’t the best thing to use anyway.
Now we come to Australia. For reasons I cannot divine, an Australian tablespoon is 20ml, fully a whole teaspoon more than the US or UK ones. You could follow an Australian recipe slavishly, and it would still turn out terrible.
Doing a bit more digging, it turns out that tablespoon measures are all over the place: see the second link below. In India in 1952, a tablespoon was 25ml. In 1979 South Africa, exactly half that. The confusion may have come from historical confusion between a table-spoon used for eating (usually owned by the diner and brought wherever they were eating) and a tablespoon used for serving food by the host (and so much larger).
[Thanks to Shaun T. for suggesting this topic.]