The decision
If the argument has made sense to you, here's a way to act on it. It has seven parts. The research behind a few of them is in the notes, but the plan as a whole is mine and hasn't been tested as a package.
Count first. For one ordinary week, write down what you drink, in units. A unit is 10ml of pure alcohol. By the NHS figures, a large 250ml glass of wine is 3 units, a pint of stronger lager is 3, and a bottle of wine at 13.5 per cent is 10. The guidance for keeping risk low is no more than 14 units a week on a regular basis, spread over three or more days, with several drink-free days. Fourteen units is about six pints of ordinary beer or six medium glasses of wine. A large glass every weeknight gets you to 15 before the weekend starts. Most regular drinkers are surprised by their total. Be one of them in private, with a pencil.
Check that stopping is safe. Go back to the first caution at the front of the book. If any of those withdrawal signs are familiar, or your weekly total is very high, talk to your GP or an alcohol service before you change anything. This isn't a formality.
Pick a start date. Make it soon, and make it an ordinary month. A month chosen because the diary's empty tests nothing. If there's a wedding in it, good.
Keep the ceremony. Decide what goes in the glass at ten to seven and buy it before the first day. It should be something you like and wouldn't have at your desk. Tonic with ice and lime, a decent alcohol-free beer, a ginger beer with some bite to it. Pour it in the good glass, sit down, and give it ten minutes. You're keeping the full stop to the day and changing the ink.
Write three plans in advance. There's good evidence that a plan in the form "when X happens, then I'll do Y" is more likely to be carried out than a general intention. Write one for each of your likeliest moments. For example, "When I get in from work, then I'll pour a tonic and sit down for ten minutes before anything else." "When someone offers me a drink, then I'll say I'm having a month off and ask for a lime and soda." "When I've had a rotten day and want wine, then I'll walk round the block and decide when I get back."
That last one deserves a word. The wish for a drink will turn up, sometimes strongly. It rises and then, if you do nothing about it, it falls, usually within the time it takes to do something else. I'm offering that as my understanding and not a cited finding. The point is that an urge is an experience you're having. It isn't an instruction.
Tell a few people. Tell the person you live with and one or two friends. The NHS suggests this, and it helps in a practical way. It's harder for someone to press a glass on you when they already know.
Line up help if you'd like it. You don't have to qualify as a problem to talk to someone. Your GP will have had this conversation many times. Drinkline is a free, confidential helpline on 0300 123 1110. The NHS has a free app called Drink Free Days, and Alcohol Change UK has a short quiz for checking your drinking. There's evidence for even light-touch help. A Cochrane review pooled 34 trials with over 15,000 people. A brief conversation with a GP or nurse left people drinking about 20 grams of alcohol a week less a year later, which is two and a half units. That's a modest effect, and it came from a few minutes' conversation.
Then, at the end of the month, while your head is clear, decide what happens next. I can see three reasonable outcomes.
You may find you don't miss it enough to go back, and carry on as you are. You may decide to drink occasionally, in which case write your rules down before the first drink. I'd suggest treating the NHS guidance as a ceiling and keeping most days drink-free. I'd also suggest not drinking to cope, and settling on the number before you start, since the first drink is a poor judge of the second. Or you may find that the month was much harder than you expected, or that your rules don't hold once you return. That's the subject of the next chapter, and it's more common and less shameful than it feels.
I can't tell you which of these you'll land on, and I'm not going to promise the month will be easy. What I'd expect is that by the end of it you'll know what the glass was doing for you and what it wasn't, from evidence you collected yourself.