With most YA spec fiction authors, when I hear they have a new book out,
 I get a little uneasy. How will the book read 
this time?  Usually YA 
authors make me wish they would write more carefully, not faster.
But there are exceptions.  One is Tamora Pierce.  When her books hit the
 United States, I'm the first in line either at B&N or the library, 
depending on finances.
Another is Douglas E. Richards.
The third installment in the Prometheus Project series is out, and, boy,
 did I dance when I got my copy. That was an overbooked weekend, what 
with family events and work, so it actually took me over 48 hours to 
finish the book.  Then it's taken me over 48 
days to figure out how to
 review it without spoilers.
The short version: GO BUY IT!
The longer version:  In "Prometheus Project: Stranded", Douglas E. 
Richards once again shows a writing ability that recalls the masters of 
science fiction:
- Smart teenage protagonists who really act like smart teenagers, rather than like adults or like Wesley Crusher.
 - Scientific concepts, explained simply and elegantly, that play central roles in the story, and
 - 
An apparently straight-forward plot that somehow includes puzzles anyway.
 
The Prometheus Project is a government installation investigating an 
alien city deep underground.  Portals in the city lead to other planets,
 and half the team is stranded on an alien world where the local 
predators have suddenly gone from ignoring humans to hunting them down 
with prejudice.  And back home, a mastermind has gotten hold of an alien
 device and appears to be intent on destroying the project and taking 
over the world.
Widely read readers may recognize echoes of Harry Harrison's Deathworld,
 but I can reassure you that its not the same cause that leads to a 
similar effect.  And, like his earlier books, Richards includes some 
totally fair puzzles that you have enough information to solve, if you 
want to. Then again, if that's not your bag, you can just enjoy a fun 
ride.
YA readers may also enjoy the gentle romantic interest and the two new 
teen characters - sisters with their own fascinating scientific 
experiments going.
All in all, a worthy work.  And two words for the Author:
WRITE MORE!