TO WHAT END, I scream, sobbing into my keyboard. It was so. fucking. goofy. And now it's nothing. Where has my lost youth gone? Must all things inevitably pass into death?
Nah, don't mind me. I'm just being super dramatic, because the Psionics Handbook doesn't have a lot of drama to it. It's just a completely regular book about a kind of superfluous alternate magic system that's a little more versatile (because it uses spell points instead of leveled slots) and a little less strong (because a lot of the powers don't scale with level) than the default. It's got a different sort of vibe than regular D&D magic, even if it's not to the degree that the 2nd edition supplement had. There's still a little bit of the new age, soft sci-fi, crystals and psychic aesthetic, but it's been diluted by 3rd edition's implicit dungeonpunk genre. Essential powers like telepathy and telekinesis are joined by very spell-like powers such as (Otiluke's) Telekinetic Sphere and Teleportation Circle. Compared to 2nd edition's selection of powers, it's more complete, but I definitely got the feeling that the gaps were often filled with whatever spell was close enough to what they were going for.
There's more to psionics than just being an alternate spell list with an alternate resource management system . . . but there really shouldn't be. Rolling a d20 to establish your powers' save DC is an extra step in resolution that winds up being roughly equivalent to the standard method in the long run, but at the cost of being randomly better or worse in a way that's unlikely to be narratively satisfying. And giving each Discipline of psionic powers its own key ability is something that could work if psionics are the only supernatural power source in the setting (so that there is a desirable niche for each of the six subclasses), but which winds up making the psion weirdly uncompetitive with other magic users.
Also, psionic combat is back. Somehow, it's even more niche than it was before. And it's completely vestigial, because it's not even used to make telepathic contact. Instead, it's just a strange subsystem that allows psionics-users to deal ability damage to each other, while non-psionic characters are more or less immune. Again, this is something that could work if psionics was the only supernatural ability available - like maybe the process of opening your mind enough to use psionics also renders you vulnerable to psionic attack, and that's just part of the price you pay for being able to do impossible things - but you can be a wizard or a druid and not have to deal with this bullshit, so it's unclear why the mechanic even exists. It's probably just because it was in 1st and 2nd edition and people were going to be expecting it.
I'm kind of at a weird place with this book, because I liked it just fine, and with the exception of the psionic combat system, there was nothing I particularly disliked about it, but I also know that the very next D&D book I'm going to read will be a strict improvement. The Psionics Handbook is not just a book from an obsolete edition, it's an obsolete book within that edition. In every other use case besides the precise one I have at this very moment, reading it would have been a complete waste of time. But that seems a harsher judgement than is really merited here. It's flawed enough that the Expanded Psionics Handbook probably would have been necessary, even without the transition to 3.5. Nonetheless, it's kind of cool. You're basically a wizard, but you're doing things with crystals (in fact, your familiar is an intelligent crystal with legs). You can summon ectoplasm. You can kind of being a mystic or a hippy. For a period of no more than three years, in the early 2000s, it was a useful thing to have.
Ukss Contribution: Some goblins have a rare genetic mutation that turns them blue and gives them psychic powers. I don't love the backstory (most are killed out of fear, but some wind up mind controlling their way into positions of authority), but I do like the imagery. A blue goblin, waving a crystal, doing new age stuff. I think they might be perfect residents of Ukss' moon.