As of today Hold the line: Crash course has left Amazon unlimited and I have released it onto Smashwords. Unfortunately, this means there is no longer a 'free' way to read the book.
I made this decision based on sales the last two months. The first month fall off was about what I expected, the second was about 3/4 what the second month was and this month the reader base in kindle unlimited is less than 10k pages read.
On the positive side the dwindling sales lit a fire for me to set up the physical book. It should be out sometime in the next few days, if not then by the end of the week.
Thanks for reading!