You'll find a ton of stuff with Google, though much of it is a little adulterated. Lots of people recognised the value in Maltz's work and many spawned methods of exploiting it. Some of it is fine. It's probably mentioned in Wikipedia.
A copy of his book titled The New Psycho-Cybernetics by Maxwell Maltz is attached. This is from the library and is free to download. If you want a different file format, PDF or Mobi for example, they can also be downloaded from here:
Just finished to read it the 2nd time, to soak it up a bit more..
It seems like Mark Douglas stole half of his writings from Maxwell T in the Z is readjustment of this mostly.. And if not, then on his own he arrived to pretty similar conclusions..
I'm delighted that you like Maltz. I think he has been under-acknowledged very broadly. He made a significant contribution to the self-help revolution and a lot of what has followed in both that arena and in professional circles owes him some thanks. Perhaps his biggest crime was being an MD, and a mere surgeon at that. This probably didn't go down well with psychiatry and psychology so they try to ignore or belittle his work. Shame really, it's quite good.
There is plenty in psycho-cybernetics that can help traders get their acts together. It will come as no surprise that it will appeal most to the successful people, or those clearly on that path.