From the introduction:
The idea of psionics has evolved tremendously since it's introduction in 1st Edition as a 'sub-class'. In the days of 1st Edition it was about as common to have a character with psionics as it was to have a bard in the party. Since 2nd Edition, the whole thing has stayed the same, the chance of having a character with psionics still is the same chance of having a bard in the party. Luckily for all of us, bards have become possible for characters at 1st level and the psionicist character class was also born. The psionicist opens up new doors of possibility with their ability to penetrate any magic resistance. These characters can quickly make enemies of any mage foolish enough to tangle with them. Like mages though, they are week at lower levels.
The PDF version of the document is distributed as a ZIP archive containing numerous TTF (True Type Font) files - unfortunately, these must be installed on the local machine to render a usable PDF document.