From the back of the book:
Each JTAS volume is a treasure trove of information and game additions for Traveller, including adventures, new ships, alien creatures from across Charted Space, philosophical musings on the big empires, histories, different takes on familiar equipment, new vehicles, characters to be met in starports, playable alien races, and much, much more...
Amongst the many articles in Volume Three, you will find:
Cartridge Laser Weapons, for those wanting to avoid heavy power packs
Zhodani Military Organisation
The nitty-gritty of jump drive operations
Engage in electronic warfare in War in the Fourth Dimension
The Tvastar Manufactory Ship, a vessel designed for instant colonisation
The chance to enact a prison break in Rescue on Ruie