I haven't been around for awhile and I am seeing a new book type: perfect paperbacks. What exactly are those? A new size? 

Here is what I found on the web

 "Perfect Paperback" simply refers to the binding process .It has nothing whatsoever to do with the book's condition.It's a type of binding often used for paperbacks where the spine is glued. Since it's the most commonly used sort of binding for paperbacks, chances are there's no difference between the two assuming it's a recent book.

Read more: http://wiki.answers.com/Q/What_does_'perfect_paperback'_mean#ixzz21my5eZt0

Perfect binding means the glue holds the pages and cover together.  It's not "perfect" at all, it's a hideous binding and the easiest to fall apart, in my opinion. 

I can just see an RC.....

"I will not accept Perfect Paperbacks"

-RD

Thanks, now I know what PP means in front of paperbacks that I've seen lately on Amazon, was wondering what it meant. LOL, Rob, can you imagine?

ROFL Rob.

I also thought they were that odd new size, same as a pocketbook except taller.  They don't fit on some of the standard book shelves.  Advertized as a more 'comfortable' and readable format, I didn't realize the designation also referred to a manufacturing process.

lol Rob!

My understanding is that "trade" paperbacks refer to the larger size, and "perfect" paperbacks is the binding.  Most perfect paperbacks are also trade sized.

I have been looking at self publishing paperbacks and I think its Lulu.com that lists Perfect bound http://www.lulu.com/publish/books/?cid=nav_bks  Has nothing to do with size.

I believe that Perfect Paperbacks refers to the binding only, as Xengab say above.

The taller mass-market paperbacks that started coming out a few years ago are called Premium paperbacks.   See the link for the articles from Penguin:  http://www.prnewswire.com/news-releases/penguin-group-usa-announces-innovative-new-paperback-format-penguin-premium-54036107.html    Supposedly this new size of paperback (for which they charge an extra $2) is easier for the eyes to read (more white space on the page) and uses higher quality paper.   But I've heard some complaints that they are actually harder to hold.    The publishers only do this for the mega-best-selling authors - like Steven King.    At least one best-selling author put her foot down and refused to let her books be issued in premium MMP size - Nora Roberts.   But of course, Nora's book usually come out first in either trade size or hardback, so the publishing company still makes plenty of $ from her books.

"Trade" originally referred to the paper and binding quality and now commonly to paperback books of larger height and width.

"Premium" and "Comfort" refer to the taller, but same width as the common mass market book.  Some of these are bound just as cheaply as the MMP and hard to hold IMO because they don't lay open easily, but the ones that are made with good binding really are easy and more comfortable to hold. 

"Perfect" refers to a binding difference, though they may also vary their size with the binding sometimes.