Encyclopedias, Almanacs, Transcripts, and Maps
- Iron Minerals
- Iroquois Religious Traditions
- irrational number
- Isaac the Syrian
- Ishrāqīyah
- Islam: Islam in Andalusia
- Islam: Islam in Central Asia
- Islam: Islam in China
- Islam: Islam in Modern Europe
- Islam: Islam in North Africa
- Islam: Islam in South Asia
- Islam: Islam in Southeast Asia
- Islam: Islam in Sub-Saharan Africa
- Islam: Islam in the Americas
- Islam: Islam in the Caucasus and the Middle Volga
- Islamic Law: Personal Law
- Islamic Law: Sharīʿah
- Islamic Religious Year
- Islands
- ISO 14000: International Environmental Management Standards