Initially, this book was intended to give advice to my children about their works or everyday lives. There might be many problems and questions unanswered for a considerable time until they finally find solutions and answers through their own experience. It might be the same with other youngsters who began their works recently. So, I would like to help them find their ways with more ease by showing them where and how people make errors and meet failures.

In this book, I introduced some new concepts, such as 'signal process' or 'signal and action pole', which could help us to find diverse causes of errors and failures more effectively. Also, I suggested some remedies that could be employed when we should face such problems in the signal process. Though many of them are based on my limited experience and observations, they might be able to enlighten young people's agony or burden to a certain degree.

Reading this book, I hope, young people could better understand the workings of the society they live in and find out solutions and answers more quickly. Additionally, I hope young people could develop their own tools or frameworks to deal with various kinds of questions and problems in the signal process with more confidence.

Taesoo Bae