from my understandings, and research.... I think there is a number of 'methods' that are similar, but slightly different.

Controlled Crying has been explained, where you leave a baby for increasing amount of time before returning to them. I think this method is becoming less popular, although it does work for many people.

Controlled Comforting - is where you stay with the baby until they are calm, then leave the room (not for any particular amount of time). You listen to their cries... and when they are distressed you return and calm them down. There is not set times for crying or comforting. Because of this Tresillian are renaming this method something else (forgot what). This is the method I was taught at QEC sleep centre, and has been really effective.

There are other methods like
Camping out... where you sleep in the same room as a baby and move a bit further from their cot each night.

Extinction (like Kelly mentioned above) - and I think this method is becoming really extinct!

And there are the comforting methods... like rocking and feeding your baby to sleep, co-sleeping etc.

Each to their own, and I think mothers should do whatever they are comfortable with. Sometimes the 'controlled' methods don't work for some - and sometimes the 'comforting' methods dont' work.

Mothers should know that there is help if they need it. Some mums can cope with sleep deprivation... some can't. So if any mum is not coping, talk to your maternal nurse, GP, and if you've got the energy - read books.