No. You're arbitrarily locked out of it, for some reason. It's doubly frustrating because
Lethian's Crossing is full of bugs if you go there without having a main quest to go there.
So currently, 9 times out of 10, your choice is to either push off going to Lethian's Crossing until you've done the first major main quest for your faction (if any), and then go to Lethian's Crossing, but then never go to the Burning Library, or you go to the Burning Library and then go to a screwy Lethian's Crossing afterwards. I've heard that there are circumstances that lets you get sent everywhere, but I haven't experienced it.
I have, hands down, never played any CRPG with so many bugs and so many narrative issues as Tyranny. The game simply wasn't finished, and as opposed to Obsidian's earlier games that were "unfinished", the unfinished-ness of Tyranny is spread throughout the entire game, instead of just being localized to the very end of the game (as was notably the case with KotOR2, MotB, and AP).