Book is addressed to two different audiences: physics community; and non-scientists interested in physics. To accommodate non-scientists minimal math is used. Whenever it is used it is accompanied with word descriptions to explain what it means. In addition each chapter is preceded with simple non-math descriptions of what chapter is saying.
Main theme of book is that the machinery of gravity is all matter is accelerating forever. The book explores this idea, shows it is a feasible interpretation of facts, explains why this is true, applies the teachings to six problems in physics finding simpler solutions for them, and solutions for several where none are at present are known. The six are: (1) Bending of starlight; (2) Advance of Mercuries perihelion; (3) Explanation for behavior of spiral galaxies, (4) Expansion of earth, (5) Anomalous acceleration terms of Pioneer 10 and 11, (6) Accelerated expansion of universe.
The book starts by citing Einstein's metaphor of observer in accelerated chest unable to distinguish that state with his being at rest on the earth. This was his Principle of Equivalence that started his development of his gravity theory (General Relativity). Obvious/intuitive rejection of this idea is that Newton's gravity law cannot be violated and it would seem (for example) that if I had two spheres of same size, but different densities, the denser sphere would have to get larger than the other one to accommodate its greater gravity field. I use Newton's law to show one's intuition is wrong . They stay very nearly the same size because (from Einstein 1905) nothing can go faster than the speed of light and what remains almost time invariant is the ratio of sizes. End up with two simple equations; (1) Exact size of any object after a long time has passed; (2) Approximate size after a long time has passed. The second of these is the commonly used definition of size.(time lapse for a pulse of light to travel the length of some object).
THE DIFFERENCE BETWEEN THESE TWO EQUATIONS IS THE SMALL QUANTITY THAT BECOMES MEASURABLE UNDER CERTAIN CONDITIONS AND CAN BE USED TO TEST IF THIS EXPANSION IDEA IS VALID OR NOT. IT ALSO IS USED IN EACH AND EVERY ONE OF THE SIX EXAMPLES DESCRIBED JUST ABOVE TO FIND SOLUTIONS.
The first part of the book explores how think about gravity in these terms and supplies additional reasoning (mainly related to the second law of thermodynamics) why this view of gravity is possibly (probably) correct. The middle part of the book applies the concept to the six physics problems as stated above. The last part of the book critiques all of it making clear that further testing is needed. The expansion of the earth chapter suggests one appropriate test. An essay on truth is added as a final item.