This technique was introduced by a well-known time-management specialist, Brian Tracy, in his book "Eat That Frog! 21 Great ways to stop procrastinating and get more done in less time".

He noticed that the ability to select the most important task at each moment and then to start on that task and get it done both quickly and well will probably have more of an impact on success than any other quality or skill a human can develop.

The technique was named after an old saying which is "If the first thing you do each morning is to eat a live frog, you can go through the day with the satisfaction of knowing that that is probably the worst thing that is going to happen to you all day long!". In case of time-management, this "frog" means the task that you are most likely to procrastinate on.

It has been also said that "If you have to eat two frogs, eat the ugliest one first!". It means that if you have two important tasks before you, start with the biggest, hardest and most important task first.

Very often the "frog" means not a very important, but unpleasant and unavoidable task. Discipline yourself to start each day by eating the frog and you can eat all of them one after another.

Of course, it is very important to begin immediately and then to persist until the task is complete before you start on something else.