Best Maths Books for Non-Mathematicians I'm not a real Mathematician, just an enthusiast. I'm often in the situation where I want to learn some interesting Maths through a good book, but not through an actual Maths textbook. I'm also often trying to give people good Maths books to get them "hooked".
So the question: What are good books, for laymen, which teach interesting Mathematics, but actually does it in a "real" way. For example, "Fermat's Last Enigma" doesn't count, since it doesn't actually feature any Maths, just a story, and most textbook don't count, since they don't feature a story.
My favorite example of this is "Journey Through Genius", which is a brilliant combination of interesting storytelling and large amounts of actual Mathematics. It took my love of Maths to a whole other level.
Edit: 
A few more details on what I'm looking for.
The audience of "laymen" should be anyone who has the ability (and desire) to understand actual mathematics, but does not want to learn from a textbook. Obviously I'm thinking about myself here, as a programmer who loves mathematics, I love being exposed to real maths, but I'm not going to get into it seriously. That's why books that show actual maths, but give a lot more exposition (and much clearer explanations, especially of what the intuition should be) are great.
When I say "real maths", I'm talking about actual proofs, formulas, or other mathematical theories. Specifically, I'm not talking about philosophy, nor am I talking about books which only talk about the history of maths (Simon Singh style), since they only talk about maths, they don't actually show anything. William Dunham's books and Paul J. Nahin's books are good examples.
 A: The Shape of Space by Jeffrey Weeks is really great.
A: If you are willing to invest a bit of time, a lot of Conway's books are very good. I especially recommend


*

*Winning ways for your mathematical plays

*Symmetries of things
A bit less "story" but still quite a lot of fun is Robert Lang's Origami design secrets. 
I also recommend James R. Newman's The world of mathematics. But be warned, while the content is not very technical (indeed, many articles in the collection are from public lectures of famous scientists), it can get a little bit dry at times. If you are patient enough for it, it is a very good companion to Courant and Robbins' What is mathematics. (It is sort of like the Princeton Companion, but older and slightly more down-to-earth). 
Lastly, you can also try the various books and articles by Brian Hayes. 
A: Conceptual Mathematics: A first introduction to categories
by F.William Lawvere and Stephen H. Schanuel
A: I will warmly recommend Mathematics: Its Content, Methods and Meaning, edited by Alexandrov, Kolmogorov and Lavrentiev, with contributions from many others. It's excellent and very affordable.
A: As an undergrad, I read a fair number of pop math books. The best by far was Ash and Gross' "Fearless Symmetry". This book is very beautiful. It sustains a nice level of rigor while being approachable by those who aren't professionals. Additionally, it weaves the tale of one of the most beautiful recent stories in mathematics. Everyone I know of who have read the book have found it wonderful.
A: Definitely, "Elementary Differential Equations" by W.Boyce and R. Di Prima, as it covers a mathematical subject which is used in many applied science disciplines in a way that makes it understandable to non-mathematicians. 
Edit (1/2/2015): I recently got involved with mathematics of social networks. A nice introductory book for anyone interested in this fascinating topic is "Networks, Crowds and Markets: Reasoning about a highly connected world" by D. Easley and J. Kleinberg. A preliminary draft version of this book is available here.
A: I've read and enjoyed some of the titles mentioned by Dunham (who balances motivations and mathematics really well; Euler: The Master of Us All was particularly good) and Stewart. Maor and Nahin also have some decent accounts. The former's book Trigonometric Delights sparked an interest in me on the history of maths back when I read it during high school, but it doesn't shy from actual derivations and mathematical reasoning.
Possibly the best book I've come across of this type however is Julian Havil's Gamma: Exploring Euler's Constant. It was one of the first such accounts I'd read, and revisiting it recently I found it just as informative as ever. In place of biography alone (though there are plenty of fascinating historical and anecdotal titbits), Havil investigates connections through mathematics via the more mysterious of 'Euler's constants' (the Euler-Mascheroni constant as it's called). It's somewhat like Nahin's book on $i$, but Havil's treatment is more cautious and farther-reaching, if slightly more demanding.
A: The road to reality Roger Penrose
Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter
A: Possibly this may not really qualify as presenting much interesting maths, but I think Hardy's A Mathematician's Apology should be on the must-read list.
A: The Drunkard's Walk: How Randomness Rules Our Lives by Leonard Mlodinow is one I'd like to read again. 
In it Mlodinow (a physicist) explains randomness as well as statistical principles and methods; he is very good at pointing out misconceptions about randomness and providing clear examples of how and why you should avoid them. 
A: My favourite writer is Morris Kline who wrote books like 'Mathematics in Western Culture' and 'Mathematics for the Nonmathematician"
A: Same as me. After so far and so many the books I've read about math. I think the best option for is "Mathematics - Its Content, Methods, and Meaning" by A. D. Aleksandrov, A. N. Kolmogorov, M. A. Lavrent'ev. It's a russian translated book. It came with 3 part. The book cover all major topic in maths. That is the best maths book I ever found. :-). And here some advice from another maths enthuast https://medium.com/@amathstudent/learning-math-on-your-own-39fe90c3536b.  
A: As a computer scientist with an interest in mathematics I liked the The Princeton Companion to Mathematics, though it is a heavy book and not always light reading. 

A: I've been successful in using Courant and Robbins' What Is Mathematics? An Elementary Approach to Ideas and Methods for adults who have not had a math class for a few decades, but are open to the idea of learning more about mathematics. 

Some sections are too advanced for someone with only high school mathematics, and many more will appear that way to the person at first, but do not actually rely on anything beyond high school mathematics.
A: I think any book by John Allen Paulos would be something any Math enthusiast could enjoy and learn from.
A: Journey Through Genius

A brilliant combination of interesting storytelling and large amounts of actual Mathematics. It took my love of Maths to a whole other level.
A: Paul Nahin has a number of accessible mathematics books written for non-mathematicians, the most famous being


*

*An Imaginary Tale: The Story of $\sqrt{-1}$

*Dr. Euler's Fabulous Formula (Cures Many Mathematical Ills!)
Professor Ian Stewart also has many books which each give laymen overviews of various fields or surprising mathematical results


*

*Professor Stewart's Cabinet of Mathematical Curiosities

*Professor Stewart's Hoard of Mathematical Treasures

*Cows in the Maze: And Other Mathematical Explorations

*Does God Play Dice? The New Mathematics of Chaos
A: How to solve it by G. Polya.
The Value of Science by H. Poincare.
Symmetry by H. Weyl
Flatland by E. Abbott
Chaos: Making of a New Science by J. Gleick
A: I think that a non-mathematician could appreciate T.W.Körner's book The Pleasures of Counting; but I still believe that the collection of "Mathematical Games" columns from Martin Gardner are the very best thing.
A: One's that were suggested to me by my Calculus teacher in High School. Even my wife liked them and she hates math now:


*

*The Education of T.C. Mits: What
modern mathematics means to you

*Infinity: Beyond the Beyond the
Beyond
Written and illustrated(Pictures are great ;p) by a couple: Lillian R. Lieber, and Hugh Gray Lieber. These books were hard to find before because they went out of print but I have this new version and like it a lot. The books explains profound topics in a way that is graspable by anyone without being dumbed down. 
Godel's proof is one I enjoyed. It's was a little hard to understand but there is nothing in this book that makes it inaccessible to someone without a strong math background.
Keeping with Godel in the title, Godel, Escher, Bach: An Eternal Golden Braid while not just about math was a good read (a bit long ;p).
The Music of the Primes: Searching to Solve the Greatest Mystery in Mathematics  It describes the Riemann Hypothesis and people who were involved with it somehow. My favorite part was learning about the people who attempted to solve it. Many I never heard off before this book. (Side not: I'll have to read pguertin suggestion, sounds in like a similar but more profound book).
A: John Derbyshire's Prime Obsession is about Riemann's hypothesis. One of the stated goals of the author is to explain what "all non-trivial zeros of the zeta function have real part one-half" means to readers who have no background in calculus. Odd-numbered chapters tell the story of how Riemann came to his hypothesis, and even-numbered chapters are more mathematical in nature.
A: I think Mathematics : A very short Introduction by Timothy Gowers is a very interesting read. As such, it's not something you "learn" from, but it makes for a very short and sweet introduction to someone who is just curious about mathematics. (Also its also a great read for people who actually do work in mathematics, because that's where I lift my examples from, when I explain to my family and friends what I am doing!) ;)
A: Have a look at https://mathoverflow.net/questions/8609/favorite-popular-math-book for other opinions
A: I'm surprised nobody has mentioned Mathematics and the Imagination by Edward Kasner and James Newman; originally published in 1940, still available in an edition from Dover. Among other things, the book that introduced the world to the name "googol" for $10^{100}$. It's a classic, and I've never heard anything bad about it. The book is meant for non-mathematicians.
I second the recommendation of Martin Gardner's columns as a follow-up. 
A more recent addition to this genre is The Calculus Diaries: How math can help you lose weight, win in Vegas, and survive zombie apocalypse by Jennifer Ouellette; it was reviewed favorably in NPR's "Science Friday"; written by a non-mathematician who never got through Calculus in school, also for non-mathematicians. I've heard some minor criticisms of the style, but otherwise generally positive reviews.
A: I rather enjoyed Professor Stewart's book [1]. Take a look at it; I hope you enjoy it.
I have blogged about a selection from his book, you can view it at [2]. This is just one of the many different mathematical concepts covered in the book. It is more of a fun book than lots of theory. It will get you to think.
[1] Stewart, I. (2009). Professor Stewart’s Hoard of Mathematical Treasures. New York: Basic Books.
[2] http://www.tylerclark12.com/blog/?p=159
A: Here's what you're looking for. It's an amazing back, and you'll be blown away by all the stuff mentioned in here:
http://www.amazon.com/Math-Book-Pythagoras-Milestones-Mathematics/dp/1402757964
A: You might be interested in "Uncle Petros and Goldbach's Conjecture", a 1992 novel by Greek author Apostolos Doxiadis. This book has got a good story, and also discusses mathematical problems and some recent history of mathematics. http://www.amazon.co.uk/gp/aw/d/0571205119/ref=redir_mdp_mobile/278-8223441-9186456
A: I'm quite partial to Scott Aaronson's 'Quantum computing since Democritus'. It covers many interesting ideas in logic, complexity and computing. It explains things clearly, but does not shy away from the mathematics when necessary.
A: My recommendation is Great Formulas Explained by Metin Bektas (as well as the second volume More Great Formulas Explained). It's a nice collection of formulas from mathematics, physics and economics for non-mathematicians with lots of examples on how and where to apply them. A little bit of algebra is sufficient to follow the text.
A: 
My mom's friend give me this book while i was finishing the last year of high scholl. At the beginning i wanted to be an engineer. When i finished to read that book i change for math.
