Other Books
Lobachevski Illuminated
A historical introduction to nonEuclidean geometry developed in the midst of extensive commentary on one the subject's foundational documents: Lobachevski's Theory of Parallels.
Winner of the Mathematical Association of America's Beckenbach Book Prize in 2015.
The book can be purchased at Amazon or from the website of the American Mathematical Society.
Precalculus Made Difficult
Algebra, Coordinate Geometry, Functions, and Trigonometry.
Learn 'em well! The fate of the free world depends on it!
All of highschool mathematics in one 200page textbook.
Read it right here as a free pdf. If you like what you see, you can support a starving math teacher (or at least one who might have skipped lunch) by purchasing a print copy for $17 at Amazon.
Infrequently asked questions
Full Frontal Calculus
Why should I purchase a physical copy when I can download the pdf for free?
The reasons are legion. To take just a few examples:

Holding a physical book in your hands encourages serious, active reading. 
A conspicuously displayed copy of Full Frontal Calculus will impress that pretty girl (or handsome lad) in the coffee shop. 
Physical books absorb (and later, return) some of your experiences in ways that ebooks do not. Years later, when you take Full Frontal Calculus down from your bookshelf, its old familiar feel in your hands will stir dormant memories. As you read again the old notes in the margins scribbled by your younger self, and see again the odd coffee stain or spatter of tomato sauce, you'll find yourself murmuring, "Yes. I remember, I remember." 
When you buy a physical copy, I will have the satisfaction of seeing its sale on Amazon. You, in turn, will have the satisfaction of having caused my satisfaction. With the royalties I earn from your copy, I'll be able to afford a cup of chai. When I drink it, I'll think of you. (And you'll have the pleasure of thinking of me thinking of you as I drink my chai.)
Is that an avocado on the cover?
No. It is a small stone, which is precisely what the word "calculus" means in Latin. (May God protect you from renal calculi.)
What do you mean by "an infinitesimal approach" to calculus?
An infinitesimal is, by definition, an infinitely small number  smaller than every positive real number, yet still greater than zero. No real number satisfies this definition, so infinitesimals are not real. And yet, by developing a "calculus of infinitesimals" (as the subject was known for most of its first two centuries), mathematicians and physicists achieved unparalleled insight into real functions, breaking through the static algebraic ice shelf to reach a flowing world of motion below, changing and evolving in time. Calculus is, among other things, the mathematics of continuous change.
Precalculus Made Difficult
Why should I purchase a physical copy when I can download the pdf for free?

Holding a physical book in your hands encourages serious, active reading. 
A conspicuously displayed copy of Precalculus Made Difficult will impress that pretty girl (or handsome lad) in the coffee shop. 
Physical books absorb (and later, return) some of your experiences in ways that ebooks do not. Years later, when you take Precalculus Made Difficult down from your bookshelf, its old familiar feel in your hands will stir dormant memories. As you read again the old notes in the margins scribbled by your younger self, and see again the odd coffee stain or spatter of tomato sauce, you'll find yourself murmuring, "Yes. I remember, I remember." 
When you buy a physical copy, I will have the satisfaction of seeing its sale on Amazon. You, in turn, will have the satisfaction of having caused my satisfaction. With the royalties I earn from your copy, I'll be able to afford a cup of chai. When I drink it, I'll think of you. (And you'll have the pleasure of thinking of me thinking of you as I drink my chai.)
Why "Made Difficult"?
Because mathematics is difficult, and it was made that way. Not by me, but by nature.
General
Seth Braver? Who's he?
He's an old hand at teaching mathematics, which he has done in 10% of the United States. Among the many places he has lived, his favorite is probably Missoula, Montana, where he earned his Ph.D. (UM, 2007). Since 2010, he has taught at South Puget Sound Community College in Olympia, Washington.
Is there an email address at which I can contact you?
Indeed there is: