After the men who had falsely claimed to be casting out demons in the name of Jesus were run out of the building, wounded and naked, it was well known to all the Jews and Greeks living in Ephesus.  The result was that fear fell on them all, and the name of the Lord Jesus was magnified.  These men had attempted to do something in the name of Jesus without knowing Him, to prove that He was no more than any other man and to profit from this.  Instead, God was magnified.  If we today claim to be doing something in the name of Jesus, but either don't know Him personally or have not made sure that what we are doing is His will, then we will fail ultimately.  We can at times add "in Jesus' name" in an attempt to validate our plans.  God's  will is the only thing we can ever truly do in the name of Jesus, and then we must have faith in His ability to give us the power to succeed.  Many of those who believed came and confessed and showed their good deeds.  The made their faith public.  We need to let the world know that we are Christians, both by our words and our actions. These men who had attempted to use the name of Jesus for their own purposes were making money supposedly telling people their future.  The result of their failure was that people believed and those who had believed in curious arts brought all their books and burned them.  These curious arts were sorcery, witchcraft, astrology and anything else claiming to be a way to know or control the future.  When we become a Christian, the Ouija board and astrological charts need to go.  Burning insured no one else would be led astray by them.  The value of the books was about fifty thousand pieces of silver.  They were heavily invested in these curious arts, but they willing gave it all up for Christ.  We must never value things of this world, especially things that we know are wrong, more than our relationship with Christ.  We might say they could have sold the books and used the money for good, but they would have been leading others astray.  If we destroy something that would be a stumbling block to others coming to God,it will never be a waste.