Several months ago I picked up Mathematics for the Million [1] by Lancelot Hogben. It's an older version, printed in 1960 (and looks to be last revised in 1951) but it's an incredible book, not only explaining math, but at the same time going into the history of math and how various branches (like geometry, trigonometry, algebra) were developed, and more importantly, why it was developed. Many were the times in class when I questioned the use of, say, geometry or algebra.
This book answers that, giving the practical uses that math has been used for, including surveying, navigation, timekeeping (why a sundial works, for instance), astrogation, artillery and area calculation, to mention just a few practical applications mentioned in the book.
At a certain stage in the history of culture the eruption of a less sophisticated community proves to be a turning-point. History chooses the foolish things of this world to confound the wise, and the weak things to bring to naught the mighty. … To accept it is to recognize that every culture contains within itself its own doom, unless it pays as much attention to the education of the mass of mankind as to the education of the exceptionally gifted people.
“Chapter VII: The Dawn of Nothing” or How Algebra Began
Not to say that this is a dry text book on history and math—it does have its humorous moments, abeit it's a rather dry humor:
The French language is especially suitable for the exercise of ironical wit. The English language is especially suitable to convey scientific truths concisely. The tortuous prolixity of German diction can be used to befuddle sensible and decent people til they believe that Hegel's dialectic makes sense and Jew-baiting makes a nation prosperous.
“Chapter III: The Grammar of Size, Order, and Number” or Translating Number Language
Hey, I found it funny. It would help to remember that this was probably written just prior to World War II. Hopefully, the modern printings will keep this around; add flavor to what could otherwise be a dull book.