This is a technical article, not a psychological conclusion. These techniques are usually applied in the reconnaissance field, but for ordinary people, learning these techniques can also be very beneficial. Anyway, this is a world full of lies, doing more research can prevent you from becoming a victim of lies. Men and women in love have even more necessity to learn these skills. However, sometimes being kept in the dark is a happy thing. This article assumes no responsibility for any catastrophic consequences caused by your mastering of these techniques.