Facebook, Uber, Robinhood: all were private companies at some point. Historically, there has been no way for investors to easily buy and sell shares in private companies. With the introduction of blockchain technology, digital securities, and decentralized financial solutions, the ability to grow the private market is on the horizon. Regulators around the world are rushing to catch up and understand how to protect investors who want to participate in this market. This book reviews the regulatory, technical, and societal challenges to open this asset class to more investors in the future.