For questions about research in the decade from 1900 to 1909, not the entire period from 1900 to 1999. If the question is not only specific to this decade, use the 20th-century tag.
When tagging a date:
- Use 20th-century for questions pertaining to the general period from 1901 to 2000.
- Use a decade tag, such as 1900s-decade, if a question is primarily relevant only to a specific decade.
