Interlingua-English: Introduction

The Introduction to the 1951 Interlingua-English Dictionary extensively explains the fundamental theory and methodology behind the international vocabulary used in Interlingua.
http://www.interlingua.com/ied/

Alyssa St. James in Interlingua

Facts about Interlingua; a short grammar; tips for learning Interlingua; list of links. Also inside: a short bibliography; a history of Interlingua; and information in Spanish.
http://interlingua.htmlplanet.com/

Latino Moderne

A version of Interlingua with a more naturalistic and extensive grammar.
http://www.geocities.com/Athens/3150/latinomodernecontents.html

Interlinguano

Web-brochure for the promotion of Interlingua.
http://www.joes.com/home/interlingua/

Interlingua

A description of Interlingua, including vocabulary, grammar, community and sample phrases.
http://en.wikipedia.org/wiki/Interlingua

Interlingua

An encyclopedia article on Interlingua, including sections on rationale, history, vocabulary, grammar, community and samples.
http://en.wikipedia.org/wiki/Interlingua_language

Grammar of Interlingua

A grammar of Interlingua written by Alexander Gode and Hugh Blair.
http://members.optus.net/~ado_hall/interlingua/gi/home/entry_page.html

A Short Grammar of Interlingua

An encyclopedia article on Interlingua grammar.
http://en.wikibooks.org/wiki/A_Short_Grammar_of_Interlingua

Basic Interlingua English Dictionary

A glossary of Interlingua words.
http://en.wikibooks.org/wiki/Basic_Interlingua_English_Dictionary

Introducing Interlingua

A short course for beginners by F. P. Gopsill.
http://en.wikibooks.org/wiki/Introducing_Interlingua