Recently I published my book "New Testament Commentary by a Mathematician" with Lulu and started an AdWords ad campaign for this book. There were zero sales and I decided to put the ebook online for free download and to stop trying to sell it.
However my other book "End of Gospel" is now in preparation with a subsidy publisher.
There are several "agressive" mentiones of "End of Gospel" in "New Testament Commentary by a Mathematician", so I hope that readers of my free ebook will read the other book also.
My question: Right now I just have put "New Testament Commentary by a Mathematician" online. Should I submit/advertise it now or should I wait when "End of Gospel" is published before advertising my free ebook which refers to it?