Further information about the publication history, scope and content of these newspapers are available in William H. Earle’s articles:
Niles' Register, 1811-1849: Window On The World
This article recounts the history of the Register and the advantages it had over other, similar publications at the time.
Creating Electronic Databases From Historical Periodicals
An article examining the challenges of taking information from historical publications--such as the Register--and placing it into a database that is both easily searchable and intuitive.