These sources provide a comprehensive overview of Non-Fungible Tokens (NFTs), defining them as unique digital identifiers on a blockchain used to certify ownership, in contrast to fungible cryptocurrencies. Several texts trace the history and evolution of NFTs, noting early projects like Quantum in 2014 and the mainstream explosion propelled by the Ethereum ERC-721 standard and high-profile sales like Beeple's digital art. Crucially, the sources focus on the expanding use cases of utility NFTs beyond digital art and collectibles, illustrating their application in supply chain management for product authentication, real estate tokenization, gaming (e.g., play-to-earn models), music, and healthcare for managing personal records. The material also covers the infrastructure supporting this technology, mentioning development firms and key concepts like smart contracts, while also addressing significant criticisms such as market collapse, use in money laundering, and environmental concerns.