It was a lot of work, rufee.
Each chapter probably takes between 15-25 hours to complete the first draft.
After that, I had to submit to editors who would bounce revisions back to me for clarifications, edits, etc etc..
Then it went to a peer reviews, and a few more editors for content accuracy, clarification etc.
All said and done, I have about 6 or 7 revisions on each chapter!
What I found most difficult about writing it was finding motivation to write. I work a 40hr/week job, go to school part-time, there was a death in the family... Often times it was really hard to come home from a day full of work and school just to sit down again and keep my brain working.
I've found myself cursing these chapters as I was writing them because at times there were certainly other things I would have liked to be doing.
So on a scale of 1-10 of hardness... 1 being breathing, 10 being Navy Seal Training, I would say it's a 7. I had to test everything I wrote about, take pictures, organize my ideas, formulate the outlines... It was like a never-ending school paper
But well worth it!
It's more time and motivation than anything. Writing isn't really hard, It's explaining ideas accurately and clearly that gets tricky.