Felix Klein Protocols
"The Felix Klein Protocols" is a collection of handwritten records of the Göttingen seminar lectures of Felix Klein and his school. They span over 8000 pages in 29 volumes, and are regarded as one of the richest records of mathematical activity in modern times.[1] The previously unpublished Klein Protocols were made available digitally in 2006.[2]
A searchable index of the protocols can be found at Felix Klein Protokolle.