I have been following EU since the Kronos and Aeon journals in the 1970's, and EUT for over a year, but I really had to write a book about gravity, simply because relativity broke gravity.
I self-published a book, Redefining Gravity, using KDP so only Amazon distributes it, in either paperback or Kindle download.
The book's title comes from the need to change the definition of gravity from the current mistake of space-time, back to Newton's definition as a fundamental force.
The book documents the well verified force of gravity, including Kepler's laws of motion, whose ellipses are around a center of gravity, or the fairly accurate slingshot trajectories.
The book proceeds to note relativity was never truly verified as "more accurate" than a force, as claimed by modern physics. EUT also knows this, but, of course, the book is not just for EUT.
When explaining how protons, electrons, and neutrinos, the fundamental real particles (not quarks), react to other particles separately by mass and charge, I explored the anomaly called the atomic mass defect. This is observed when we measure atomic mass. We expect its measured mass to match the sum of its components, but they don't always match. The atom is often measured a little lighter than expected. There is only a small number, including chlorine, where the measured is greater than the sum. The "missing mass' is attributed to a conversion of energy often including a reference to Einstein. However, "extra mass" cannot be explained that way.
The book charts this behavior through the entire periodic table. The conclusion after that analysis is neutrons in a nucleus can slightly change their measured mass. This is a tiny change but is being measured.
The change per neutron varies with each element. Some sets of elements are similar, like nitrogen and oxygen. They are consecutive suggesting the change in apparent mass is driven by the structure of the nucleus. There is a possible pattern but not all elements have a valid measured mass. It was a disappointing surprise to discover quite a few elements have their atomic mass value rounded from its isotope ratio. Any rounding directly causes a mass defect.
A mass value from the known mix of stable isotopes is acceptable for chemists but not for a mass defect analysis.
In September, 2020, Wal Thornhill explained his expectation of a hollow Sun, based on his own theory of gravity. The timing was important because, in December 2017, Dr. Robitaille did a video titled "the sun is not hollow" so a conflict persists in solar theories. I disagree with Wal's theory of gravity, so I felt inclined to offer an alternative.
I posted on September 11, gravity behaves rather like electrical charges. Both forces are instantaneous, follow the inverse square rule for distance, and have constants driven by "open space". However gravity is always pulling, not alternately pulling or repelling, regardless of charge. That post became the basis for the book.
This neutron behavior suggests a change in the current atomic model and its expectations for a neutron. That model lacks an acceptable explanation for a mass defect.
The book can describe the necessary atomic changes but the book is mostly about gravity, not the mechanisms within a neutron while being in an atomic nucleus.
The book becomes one with much about the elements, some about gravity, and a little about relativity.
Perhaps, this book will not help much toward the disposal of relativity from physics. I can offer only what I can.
Gravity must be important to EU because Wal has a theory for it.