I heartily recommend picking this up.
Most of the info is good enough to be used with later versions (with some alteration depending on "which" type of traveller you're using) but it makes a very useful introduction to the Traveller universe.
This is a three part download, one makes a good option for players with the second a more in depth explanation of the traveller system even if its classic inclined (2d6) and the third deals with some adventures always a good option if you're running the game for others or would like an example of how a scenario can be developed.
All in all a good buy.
[4 of 5 Stars!]