Personally, I don't believe in plagiarism. Sort of like the way I don't believe in capitalism. It's not that I'm for or against it, I just don't believe it exists.
This comparison of Markham's book to lines from other works reads like a TA's wet dream.
And... I just don't care who he "stole" from.
And of course there's an entire genre of popular music which actually takes recordings of other artists and creates new works from them. That music is primarily illegal -- and as such it's pretty fascinating by me.
Now that this book is unavailable, I (of course) really want to read it. I mean, if it got good reviews before people discovered that whole sections came from other books, doesn't that still make it a good book?
As it turns out, whole sections of the Manchurian Candidate were lifted from I, Claudius. What if we were to find out that Hamlet and Pride and Prejudice were stolen from earlier sources?
If it's good, it's good.
So say I. And as the Lord Regent of the God Emperor of Mars, so say We all.