(Full disclosure: I was provided with an advance copy of this book for copyediting purposes. I was not involved creatively.)
Encounters ~ Plots ~ Places serves one function: providing a GM with evocative characters, locations, items, and story hooks.
The key word is "evocative." There are plenty of books that offer dry lists of characters and items, almost as though they were computer-generated. Ben Gerber describes each character, location, or item in enough detail to pique the reader's interest and clearly explain its uses. While the book is system-neutral, each element includes a standard block of basic stats: size, motivation, strengths, weaknesses, and a "power level" ranking from 1 to 10.
Better, each character, location, and item includes a set of adventure hooks, so they're easy to work into an ongoing campaign.
This is not a huge list of characters; EPP has "only" a few dozen NPCs, encounters, items, and places total. This is about quality over quantity. That is exactly its strength: each element is vivid and charged with potential for conflict.
[5 of 5 Stars!]