Seriously,this is the stuff of social scientists' dreams!
55-Year Diary Shows Life, History
This guy kept a diary for 55 years? Heck my only attempts to keep a diary lasted . . . well, two consecutive days. But this diary has such a wealth of information, I think it's going to go down as one of the more significant items in the museum's collection. A 55 year diary complete with related miscellanea like cashbooks and medical prescriptions? Holy record keeping, Batman!
In graduate school I worked at the Oral History Institute for a while, and did a bit with the collections and researchers there. The records generated by oral history are invaluable, yet by and large recorded well after important events happen - they're direct and intimate and valuable, but this . . . recollection of events as they happen, along with corroborating records? Amazing. Absolutely amazing.