Has anyone read this book about diciplining (sp?) children aged 2-12? Was thinking about picking it up, but wanted a few opinions first.
I read a few reviews on amazon, and they were pretty mixed.

The public library, or even your child's school should have a copy, as does usually the OEYC (don't know specifically about London though). There is also a DVD/VHS if you don't want to “read“. It is faster, as it is about 2 hrs long to watch.
Essentially, idea is you can't reason with kids, discipline is not a “discussion“. If they do something unacceptable, you count upto 3 (with a few seconds pause between numbers). If the child has not stopped the undesirable behaviour by the time you reach 3, the child gets a time out. No discussions, no negotiating, nothing. Simply count “1...2...3. Okay take a 5 minute time out“. The key to this technique is consistency.
I watched the DVD (got if from my DS1's SK teacher), and it was also recommended to me a few years before by my pediatrician. I think it can work, depends on you and your family. But like I said, you have to be consistent 100% of the time.
I'd borrow the DVD first, then decide if you like the method, and if you do, then buy the book. Good luck.
worked like magic for my daughter.
didn't start until she was about 2 1/2.
We use it all the time and have since DS was 2. It's not that kids' can't be reasoned with, just that it can't be done in the heat of the moment because it's not very effective. Too much talking gives them control and the chance to argue back. This is not simply the old stand-by “1, 2, 3“ bit that many parents do. If done properly it is very effective.
You count 1-2-3 and if the child hasn't stopped the behavior it's time out time and you don't talk or anything till after the 5 minutes....we did this for 6 months and DSS would get so upset and angry when we started counting it escalated him more then deescalated him which is what it's supposed to do.
It works well for certain siuations/children. But not all.
I agree with a few above, it can be the wrong thing.
I would sign out the DVD or ask your school and see if its something you could see working.
Love isn't love till you give it away.
Like any discipline method, you have to stick with it to have it work. What ever you choose, be aware that 'giving in' or letting a behaviour pass, will confuse the child and they will push more. It's not unusual forr a child that didn't have consistent discipline to act out more. We were taught it as foster parents and while I disagree with the premise of the book that children are wild animals and were are like the lion tamers, I like that it gives the child the ability to learn self discipline by learning to comply earlier in the counting.
I love it and use it with all three of my kids and the range from teens to toddler. We tried the super nanny way with the warnings but found there was more arguing then anything else. 123 magic cuts that out, the first couple days DD#3 spent a lot of time in time out it takes time and patience, now I rarely ever get to 3. I thought it was ridiculous at first but it really isn't.