Well if you are lucky you have made your way into the Archive already and you know what it is about, but in case you haven't then check out your faction choice and hit the bookstore to see what's up. You will find a book of your level buy it and then use it in your hotbar to activate the spellcaster. Each Construct/Achive Level has it's own bad guys and a mob boss that respawns often. He can also give out rare clothing objects that will help you along the way. Two rare demandable items are the Bananda from Lvl30-40 and the Sunglasses from Lvl35-45.

Faction	District	Landmark	X	Y	Z
Merovingian	Apollyon	Majesty Monument	224	1	-1514
Machine	Midian Park	Azimuth Twin Monument	1215	1	-1155
Zion	Moriah Projects	Azimuth Monument	1114	7	-74