I did a thing. Learning Proxmox VE is available in print and as a DRM-free ebook.
It’s available at the usual suspects - I link to resellers as I find them.
There’s an article published at Packt Pub’s site on “Proxmox VE Fundamentals.” This is the first chapter of Learning Proxmox VE in its entirety. Bam.
More content from the book is available at Slideshare; it’s described as a sample chapter, and is, in fact, Chapter 7 of the title. It covers Proxmox VE host and guest security and is available here.