1200-1400 fide? 1200-1400 chess.com? 1200-1400 WHERE? It is like saying (from france, but in english) the temparature is in the 40s [coldish if 40F, roasting if 40C ].
Good book for someone in the range of 1200-1400

If you're talking 1200-1400 OTB rating I would say:
Ludek Pachman's "Modern Chess Strategy"
Chernev's "Most Instructive Games of Chess Ever Played" followed by
McDonald's "The Art of Logical Chess Thinking"
Silman's "Complete Endgame Course"
and Modern Chess Openings 15
If you're talking 1200-1400 chess.com range I would suggest
Chernev's "Logical Chess Move by Move"
Heisman's "Everyone's Second Chess Book"
Silman's "Complete Endgame Course" (Do chapters 1 and 2)
Vagabond69, I took a look at some of your games (losses - they're the most instructive for figuring out what you need to work on). I'd recommend you start with these:
http://www.chess.com/eq/chess+books/play-winning-chess2
http://www.chess.com/eq/chess+books/winning-chess-tactics
http://www.chess.com/eq/chess+books/winning-chess-strategies2

from ericmitten's post, looks like he is NOT talking about 1200-1400 fide OTB. Canadian-Chess-Federation ratings??? uscf???

A good tactics book might give you more confidence to keep your pieces moving forward. Chess by Lazslo Polgar is good for 1200-1400 wherever.

For sure tactics are the most important thing, but I personally don't like books for tactics.
Yes my suggestions for a chess.com rating are easier than my suggestions for an OTB rating because chess.com ratings are extremely inflated.
I am talking about any OTB rating, though not FIDE as they start at 1600 and you can't get a FIDE rating at local tournaments. So any USCF/CFC/ECL/whatever rating will do.

As a player firmly entrenced in the range (1200-1400) you describe I can tell you that Jeremy Silman's "The Amateur's Mind" has given me much to think on and work with. Plus, his writing I find accessible and fun; it feels almost like a private tutoring session. Definetly worth a look... Just my .02 :)
Good Luck!

Your a relative beginner so u dont need anything to intense with theory or variations. I liked (Idiots Guide to chess) cant remember the auther and (play winning chess series; by yasser seirawan.) as was mentioned before if ur interested in study that isnt to intense for ur rating range. I found them to be easy enough to read and understand even when i myself was a beginner as u r....
P.S. None of its usefull unless u practice and learn from ur own personal game too!

Lots of usefull suggestions! Do not forget your local library! There are lots of excellent books for advanced beginners and improving players more or less containing the same stuff. You need to be lucky to find a book you like to read/use/study. It often boils down to personal preferences on how you like books to be written. hence, it is very nice to borrow a book from the library to better see if you like the presentation.
I've noticed a topic recently for the top 5 chess books a player should own. It was mentioned it was mostly aimed towards players 1400+. I play usually between 1200-1400 depending how much time i take and concentrate. My question is what books are best for a player within this range. My long term goal is 1500. I'm looking for books not heavy in notation and more focused on theory. I'm strong in the open but very poor in the end game and i play very defensively. Any suggestions? Thanks