Don't You Ever Read Anything But Serious Books? Volume 4

To attempt to do some justice to myself (without too much bias) Volume 4, especially, is a confusing personal mix of limitations with originality.
My adult life-time of note-taking attempted more difficult topics. Perfection was not to be thought of. If need be, it was just a question of making the best of my limitations, which I did not dwell on too much, so as not to discourage myself unduly. I knew I was attempting too much. But I clung on to the hope that I might improve. It was an act of faith, somewhat.
My physics notes spilled over into an other volume. But this fourth volume, to some extent, did change its character from volume 3. Increasingly, works on recreational mathematics were beginning to appear. Obtaining them, via the public library selection committee. I knew one or two of its members, as fellow participants of a book club, for a while. And I have one or two of them to thank for their judgment.
My amateur note-taking finally drew to a close in 2012, after some forty years of private study.
I had convinced myself that my copious notes were of no use to myself, much less anyone else.
The following year, 2014, I published my first e-book. I had thought this not possible, but managed to jump thru the (circus animal) hoops, to achieve it. I had much material from my poems and my web-site, but certainly not from my notes.
Vast tracts of these scribbles, I regarded as unusable copy, not even understood by myself. This was true, but I think I was further dissuaded by distant memories of my monumentally useless further education notes, which were essentially exam-passing attempts on forgetable topics, I had no interest in, on a sociology course.
The difference was that my amateur post-education notes were enthusiastic, or at least determined, free choices, not tied to some set curriculum, other than I set myself.
Consequently, I found, to my surprise, that I could salvage some of these notes for publication, four decades worth of them, in four volumes.
Volume 4 varied my popular physics specialisation, especially with the emergence of more popular mathematics books.
I also contributed ideas of my own. mainly in later chapters. I found, at last, that re-reading my notes did add some little something to my understanding, and that they were not completely unrewarding.