Ritson believed that man's only chance of happiness is to develop higher moral virtues of benevolence, justice and humanity by adopting a vegetarian diet.

[12][13] In 1939, Historian David Lee Clark compared paragraphs from Ritson's book to Shelley's A Vindication of Natural Diet (1813) and noted that in addition to general similarities "there are many parallels in phrasal patterns which could hardly be accidental.

"[12] Historian of vegetarianism Colin Spencer commented that Ritson's ideas about abstinence from meat-eating were not popular with the majority of people during his time, who considered his views dangerous.

[14][15] They stated that whilst writing the vegetarian arguments for his book, Ritson had used a quill plucked from a goose, ink made from insects and a whale-tallow candle.

"Milk, too, which Mr. Ritson so strongly recommends as food, is an animal production; and it cannot be procured in sufficient quantities for the use of man, without prodigious injustice to the author's clients, the sucking calves, asses and goats.

[20] Biographer Bertrand Harris Bronson commented that much of the content from Ritson's book was dubious: The unsupported assertions of voyagers all over the world, unsubstantiated opinions of quacks and cranks for the preceding two hundred and fifty years, newspaper stories of old men and women who had lived to incredible ages on a vegetable diet, and of young maidens who lived upon air: everything was grist to Ritson's vegetarian mill and apparently accepted as gospel truth.

[11] Adams noted that Ritson's last work Life of King Arthur from Ancient Historians and Authentic Documents, published posthumously in 1825 was widely reviewed as an early example of modern scholarship.