From the introduction:
The planar saying goes: "Any clueless berk can use a portal, but it takes a true blood to master a Planar Pathway". And for the most part, it's true, cutter.
Portals ain't everything they're cracked up to be, see. For one, they're subject to the Lady of Pain's whims. Usually, that doesn't amount to much, but there's many a tale of Her Serenity getting uppity with Cagers and sealing them off, or shifting them around. And the portals in the Hive particularly are notorious for changing their destinations without rhyme nor reason.
Besides, portals are often well known, and well-documented. Because they're so easy, they're also often guarded, at one or both ends. Keys can be hard to research, hard to find, or expensive.
A wise blood, then, never forgets the pathways. They've always been there, and it's likely they always will be. They're massive, expansive, and span planes. They make travel easy, are relatively safe (forget the Styx for a moment, cutter!) and don't require portal keys.
You'd not be surprised then to learn there's a whole host of bloods out there willing to guide you along these paths, for the right price of course. From the yugoloth boatsmen of the Styx to the innocent ratatosk squirrel-people of Yggdrasil, and the Planewalker's Guild of the Infinite Staircase in between, you don't usually have to shout too loud until someone drops by to help you.
Want to learn the dark? You're garnishing the right blood. Ask, and I shall tell you all I know...