Readability Note: For those concerned about readability, the file was updated on December 12, but no significant readability problems were evident in the original. the file was and continues to be readable. This is a pdf made from scanned images, but the scan is as clean as you would expect based on the style, font, and age of the printed source. There are no bookmarks, however.
The Federation Sourcebook (1994) was a useful expansion to Prime Directive, fleshing out a lot of things which players asked about when the game first launched. It added new character types (Commando, Combat Engineer), expands the material on Vulcan psionics, and adds rules and background for non-Vulcan psionics. In addition to offering a great deal of knowledge concerning the Federation and its member races, the expanded rules options and play aids, such as hit location, alternate/advanced initiative, and the ship recognition section increased the speed and ease of play while providing many more hooks and background ideas for players to incorporate into characters.