Steve Wasserman at The Nation writes about the impact of Amazon on publishing and book selling.
The article is mostly negative on Amazon. Some of the comments present a pro-Amazon view. This provides some needed balance.
The book Pre-Algebra New Math Done Right Peano Axioms was written to be sold as an e-book by the two large vendors in particular, Amazon and Barnes and Noble.
It was only while writing a book intended to be published as an e-book that the new pitch line definition of addition was invented.
The old definition from Grassmann and Dedekind is
x+0 = x
x+y’ = (x+y)’
where ‘ means the successor or next natural number.
The new pitch line definition of addition is
0+y = y
x’ + ‘y = x + y
where ‘y means the preceding number or predecessor.
It was not a matter of inventing this definition and deciding to write an e-book. It was writing the e-book and in the course of writing the e-book, inventing the new definition of addition. This was invented to avoid the complicated Kalmar definition of addition in the Edmund Landau Foundations of Analysis book.