The Firm Foundations Bible study series http://www.ntmbooks.com and related materials centers on following God's progressive pattern of revealing His character and plan of redemption within the context of history. Firm Foundations was written partly by Trevor McIlwain.
Trevor McIlwain is an author, speaker and international coordinator for church planting and evangelism with New Tribes Mission. Trevor and his wife, Fran, have served with NTM since 1965. Ten of those years were among the Palawano people of the Philippines. Seeking to find an effective means of conveying the Gospel clearly, Trevor determined to present it the way God revealed it in Scripture -  progressively, and in context of His dealing with mankind throughout history. A methodology was born -  the chronological approach to evangelism and church planting. Trevor's original multivolume series Building on Firm Foundations explains principles for a 7 -  phase program of evangelism and church planting.  It usually takes about three months to do the whole Firm Foundations program.

Study materials for adults are available in English, Spanish and other languages below:
                       
Arabic 
Chinese (Mandarin) or Chinese Traditional 
Chinese (Simplified) 
Dutch for Suriname 
French 
German 
Indonesian 
Japanese 
Korean 
Kyrgyz 
Portuguese 
Russian
Spanish 
Tamil (India) 
Vietnamese 
English Loose Leaf Version
Firm Foundations has been translated in other languages, but not all languages are for sale on the New Tribes Missions bookstore web site. Please contact New Tribes Missions about other languages.  Here are two below. 
Guarani
http://www.ntm.org/wp/dean_goddard/2008/09/11/teaching-firm-foundational-bible-lessons-in-guarani-language/
http://www.ntm.org/wp/dean_goddard/2008/06/07/after-7-years-the-firm-foundations-bible-lessons-completed/
Gujarati
http://www.ntm.org/singapore/news_details.php?news_id=44
Swahili?

A special set of materials has been created for children for child evangelism, family study or home school curricula. 

Be sure to check out the maps, charts and Bible pictures that accompany the series. 

You can find out more information by going to 
this web site

http://www.ntmbooks.com

and clicking on the link Firm Foundations in the category section on the left side of the page.

You can see the missionaries and native, national and indigenous Christians use the Firm Foundations bible studies on different videos and dvd’s which are found on the New Tribes Missions bookstore website. Titles such as EE-Taow!, The Taliabo Story, The  Mouk Story, Reachable, Taliabo and Delivered, Now We See Clearly and BFF Teaching Seminar (Firm Foundations Seminar) 
are videos and dvds found on their website.