Bunch of Linux-related ebooks available different levels of cost in this month's Book Bundle (https://www.humblebundle.com/books/linux-geek-books?linkID=&mcID=102:5b4cd4832cab4ecf412c1c75:ot:5a0e5ff71c7d4cd39aeb5822:1&utm_source=Humble+Bundle+Newsletter&utm_medium=email&utm_campaign=2018_07_16_linuxgeek_bookbundle&linkID=&utm_content=cta_button). Many are programming related but there is a couple on The Gimp and one on Inkscape and another on Blender. The deal expires near the end of July.