From the Introduction:
The World Tamers Handbook is a Traveller: The New Era sourcebook as well as several adventure campaigns built around the theme of rebuilding shattered worlds.
As a sourcebook, WTH provides referees with expanded or new information on the following subjects:
A playable planetary economic model, including agriculture, raw materials, and industrial components, fully interlinked with the characteristics of planetary environment
Star and planetary system generation and detailing
Expanded planetary survey rules that mate with the planetary economic model, allowing players to seek out worlds suited for habitation and development
Rules for acclimatization to new environments
Battalion-level mass combat rules, allowing the resolution of large-scale combat in Traveller
Archaic weapons design sequences including black powder small arms, black powder cannons, and bows
New equipment based on the new design sequences plus three new starships suited for colonization missions