First of all I'd like to thank Jouma for suggesting doing the brain symb quest to gather all of the books for the 3rd specialization. But for those of us who are squishy, there's a far easier way.
I'll start from Ado Garden. Use the teleport statue that goes to Lamenting Lagoon. NOTE: DO NOT teleport without first equipping your meta water suit that was given to you by Ergo. You will die from a massive 500 DoT from the water without it. Once underwater, make your way south to the Unredeemed Temple. You will need to jump over the cliff to get there. There are one or two stingers and/or eels on the way, nothing too overwhelming, and the stingers won't agro you unless you're practically standing right on top of them.
I don't know if there's a better way in but I usually go near the vortex (you'll know it when you see it) then turn towards the building and jump up, run around to the other side of it which puts me right in front of the door. Head inside.
Don't panic. These guys won't go agro...until you attack them first. Run north to the first door. In front of this door is a Fortuitous mob. This is the sweet spot. Camp this guy and if you're lucky like I was he will drop all 4 books in succession, along with some other tasties.
Another note: I was bugged the first time I came in, it wouldn't allow me to attack anything. If this happens go outside and come back in. If you still can't attack, someone was there before you and the mobs require a waiting period of a few minutes before they can be attacked again.
If you're feeling brave and don't want to wait out the 15 minutes or so between spawns, go into the door Mr. Fortuitous was standing in front of and when you get into the next room there are 2 more Fortuitouseseses on the left and right upper sides of the room. I got ganged pretty hard by his buddies, but chances are you'll have the place to yourself so no chance of being ninja looted. Just kill F-Man off, run back to the first room, wait about 20 seconds to lose agro by the adds, run back in and loot him in safety.
If you have any questions feel free to ask.