From the notebooks of Thomas Edison — the fourth most prolific inventor in history, and as such a ridiculously busy man — comes a five-page to-do list, handwritten in January of 1888 when Edison was still just 40 years of age. A few immediately notable entries (that is, notable to someone as unintelligent as me — I don't understand huge portions of it) include, "Electrical Piano," "Artificial Ivory," and "Ink for Blind."
(Source: The Thomas A. Edison Papers at Rutgers University; Top image: Thomas Edison in 1911. Source.)
Images: The Thomas A. Edison Papers