A Document Shepherd is an individual who provides working group-level support to improve document-processing throughput and document quality by working in partnership with the responsible Area Director.
RFC 4858 talks about "Document Shepherding from Working Group Last Call to Publication", but there's a significant part of a document's life that happens before working group last call, starting at the time that a working group begins discussing a version of the idea that's been posted as an individual draft. This tutorial discusses the job of the document shepherd, the tasks that might be involved throughout a working group document's lifecycle from start to finish, and the potential for extending document shepherding into earlier stages in that lifecycle.
Allison J. Mankin, David Meyer, Henrik Levkowetz