I'd like to find some good books, posted on PBS, as presents for my nephew (14) and niece (17). 

Suggestions?  Thanks.

Depending upon what they are interested, I would say that you really can't go wrong with Dean Koontz.  His books can be sometime frightening but the hero always goes on to fight another day and there is no graphic sex scenes or inappropriate language.  For your niece I would suggest possibly By the Light of the Moon or One Door Away from Heaven for your nephew I would say either Phantoms or Lightening.  Also good for either would be Seize the Night and Fear Nothing.

I have read almost all of his books and love them all.  I started when I was a teenager and have kept up ever since.

Hope this is helpful have a great day.

Loretta

It really depends on what they're interested in...

I remember getting into Sue Grafton's mystery books (A is for Alibi, etc.) in high school--I still really enjoy them.

My brother really got into Star Wars sequels... but I can't think of any titles right now... He also really liked Clive Cussler's Dirk Pitt adventures.

If they like fantasy, they might enjoy Christopher Paolini's Eragon...

Hmmmm The Ebenezum series by Graig Shaw Gardner is really funny. John Saul is another good one like Dean Koontz. The characters are generally teenagers.

For your niece when my niece was 14 she liked The Sisterhood of the Traveling Pants.

Here are some authors that my 13 and 14 y/o grandsons love:

Darren Shan's work, including Cirque de Freak and Demonata,

Erin Hunter

Angie Sage, including the Septimus Heap series,

Brian Jacques, including the Redwall series

Garth Nix

Eoin Colfer the ARTEMIS FOWL series

Also:    I Heard the Owl Call My Name  by  Margaret Craven

Probably  for the boy, at least, I'd recommend you do a search under advanced search under the genre Teen and pick the sub-genre they might enjoy.  , biography, series, fantasy, horror  maybe literature and fiction.  Lots of the titles are not labeled under teen but under childrens, or under  the catchall "literature/fiction" but it's a place to start and then see what sticks.  :)

These are some helpful sites for young adults: http://dir.yahoo.com/Arts/Humanities/Literature/Genres/Young_Adult/Series/

If  he happens to like vintage mysteries, this is a cool web site: http://www.series-books.com/

If you have a starting place, this site for young adult books works well:  http://www.bettendorflibrary.com/bpl-bin/series.pl

Of course:  HARRY POTTER by J.K. Rowling and HIS DARK MATERIALS by Philip Pullman and Narnia by CS Lewis.  Other cool series, depending on his reading level: PROTECTOR OF THE SMALL by Tamora Pierce, THE SPIDERWICK CHRONICLES by Tony DiTerlizzi and Holly Black.

I'd also check with your local librarian, by email or phone.  They can really give you outstanding references.

Best of luck!

Sharon

ETA:  Judy Blume writes for a broad audience, too.

One series liked by both sexes is James Pattersons Maximum Ride.

Dean Koontz Odd Thomas series is also a great favorite with teens in my area.

Click on this http://www.renlearn.com/whatkidsarereading/ and click on the link that says "What kids are reading' and an adobe file will pull up.  Just scroll through to the age group of the kids you are looking for and see what kids are reading.  The 9-12 grade starts on page 29.  This is a great resource and it certainly tells you what is popular.  Good Luck!

Great resource, April!  Thank you!

How to Build a House is getting rave reviews from teens...

I just looked at another book by her A Brief Chapter in my Impossible Life....it looks good too.