I know - I should (and will) buy the book. Hoping someone can give me a quick answer though. I typically drink one or two bottles of white wine a night. For whatever reason, I've always thought a bottle has about four to five units of alcohol. Looking around on the web, it appears that it's probably more like 8-10. Can that be right? I'm a little shocked.

There are different definitions of 'units'.

e.g. one UK unit = 10ml of ethanol
one Irish unit=12ml of ethanol (10g)
one US unit~17.7 ml of ethanol
one Finnish unit ~ 25ml of ethanol

Personally I think the UK version is the easiest to work with.
Take your favourite tipple and find the percent alcohol - white wine will typically be 11-13%, lets say 12%. There are, therefore, 12 units per litre of this wine. A standard bottle is 3/4 of a litre, so that would be 9 units.

In this part of a world, for example a standard bottle of spirits (whiskey, vodka etc) is 40% alcohol and 700ml bottles, so a bottle is 28 units. Beer is 4.3% so a standard can (330ml) is about 1.4 units. A large can (500ml) is 2.1 or so. A pint (568ml) is about 2.5 units

For me, at least, there are only 4 or 5 different types of drinking scenario - e.g. a glass of whiskey, a pint/can of beer, a glass of wine etc. You fairly quickly get used to (roughly) estimating what fraction that measure is of a bottle based on experience - e.g. how many glasses did I have before I finished that bottle of wine etc, and once you've done that and the above calculation once or twice it becomes fairly easy to track (assuming you're not too drunk to remember ) how many units you've had.

Which units you've used isn't that important - just know the (safe) target levels and keep the trend going downwards towards that target (or beyond!)

I can't remember where I got my statistics from and I'm at work now so can't retrieve my notes. But I figured from them that a 750L bottle is 6 units, with alcohol content being 8.5% alcohol (I'm a lightweight sweet riesling drinker), and I drink 2 bottles a night so that's 12 units. That's what I've been using to calculate my weekly (usually 84 units) consumption. Don't know if that helps, but as ART says, it's not the unit measure you use it's knowing your safe target levels and working on getting them down!

-petal