The document discusses the concept of deadweight loss from taxation. It explains that taxes reduce overall welfare for buyers and sellers by creating a wedge between the price buyers pay and sellers receive. This leads to a reduction in quantity traded below the efficient market level, resulting in lost gains from trade. The deadweight loss is larger when demand or supply is more elastic in response to price changes. While tax revenue initially rises with higher tax rates, it eventually falls as the tax reduces the size of the market.