The presentation of the book leans heavily on mathematics, and good understanding of some parts of the book require skills in ground level university mathematics. You manage rather well also with high school mathematics and positive attitude (or maybe also with pure positive attitude). Both classical gravitation theory and general relativity theory are treated using easier mathematics than in standard presentations. The basic structure of the theories is presented clearly in the book. Some new results with relation to planet orbits are presented in the book. von Kivi, U.
The author of the book has a university examination with major subject in physics and minor subject in mathematics, but is not a professional in gravitation theory. Because Finnish name 'Uuno' means one in Italy or ein in Germany and Finnish word 'kivi' means stein in Germany, the pseudonym Uuno Kivi may be interpreted as Einstein. 'Uuno' means also stupid in Finnish so that if the reader don't like the contents of the book he/she may interpret the pseudonym as 'stupid as a stone'.