As more and more purchases are made over the Internet, states are looking for new ways to collect taxes on these sales. While there is a common misperception that states cannot tax Internet sales, the reality is that they may impose sales and use taxes on such transactions, even when the retailer is outside of the state. However, if the seller does not have a constitutionally sufficient connection ("nexus") to the state, then the seller is under no enforceable obligation to collect a use tax. While the purchaser is still generally responsible for paying the use tax, the rate of compliance is low. Recent laws, often called "Amazon" laws in reference to the large Internet retailer, represent fresh attempts by the states to capture taxes on Internet sales. This book provides a constitutional analysis of "Amazon" laws and taxation of Internet sales; state taxation of Internet transactions; and testimony on the hearing on the constitutional limitations on states' authority to collect sales taxes in E-commerce.