In previous supplements like "the book of worlds" the spiritual reflection of our ideas, myths and hopes reflected in the immense Umbra were terrifying or beautifull. Power awaited in every corner, and once a coven of player characters found some utopia it was frequently quite difficult to get them out of there "in character" - why should my Celestial Chorus Sister Amanda get out of Heaven??? There were also facilitators like the grand hall of endless gates or the inventium that were really far fetched and unbalanced.
The developers of Mage the Ascension solved all that masterfully with the Avatar Storm. Now the simple act of sidestepping is extremelly dangerous! Umbral voyages are made with a purpose and objectives (no sightseeing). The disembodiment solved the problem of long stays (anyone staying for to long in the Umbra, loses contact with the body and turns into a spirit - yes...you die).
Now the Umbra is again a place of terror, awe and enchantment. Complex politics and interaction with patrons are required for characters wishing to ascend to the upper astral realms and navigate with safety.
This book describes so many interesting places and characters that you will wish your players go to the Umbra in search of power and knowledge often. It also includes a short story (the master's voice), Some interesting Umbral residents and their motivations, rotes, merits & flaws and umbral wonders.
Great book with excellent cover art by Lawrence Snelly and very good interior art.