The study of Probabilistically Checkable Proofs, starting with the discovery of the PCP Theorem, is a cornerstone of modern computer science, with impact on complexity theory, algorithms, and cryptography. Born as a purely theoretical notion, mostly used to prove hardness of approximation results, PCPs are now becoming a widely deployed tool in blockchain platforms. The workshop will touch the past, the state of the art, and future of PCPs. Topics will include: hardness of approximation, PCPs in cryptography and blockchains, no-signaling PCPs, PCPs in P, and Boolean function analysis.