From publisher blurb:
Walk through fantastic realms, from hot deserts to stormy jungles and the cosmos beyond!
The Realmwalker’s Handbook introduces a new prestige class, the Realmwalker, a planar traveler and explorer which can survive the harshest of climates and open pathways to faraway places.
New options and class archetypes, including the Mistwalker Symbiat, an elusive infiltrator. Barbarians can cloak themselves with the power of the stars themselves while eliciters harness a new emotion, the crusing squall of futility in the vastness of the cosmos. New feats and talents for traveling and mapping new and undiscovered places and harnessing planar energies. New items allow adventurers to explore a wide bazaar of exotic elemental implants and focus components.
This handbook also contains two large sections for worldbuilding: Planar Magics and Ley Lines. Planar magics are localized restrictions on spellcasting which may force certain requirements on the creation of magic. Ley lines are primordial pathways from which energies may spill out, creating manifestations, empowering spellcasters, and creating unique phenomenon. New rituals are also included to interact with these planar phenomenon, from locating and mapping ley lines to teleporting through them or even permanently binding new ley lines to the terrain.
This supplement is a Pathfinder 1st edition product using Ultimate Spheres of Power, Spheres of Might, and Champions of the Spheres.