If Schama's Citizens is postgraduate level reading on the French Revolution, this would be approximately the equivalent of writing in crayon.
Davidson name checks Schama and Hibbert early on, sulking that their accounts of the French Revolution carry a tone of disapproval, which he feels is unjust. Yet Davidson never once engages with those accounts, which were infinitely more insightful, and written by men with far better understanding of the topic than him. Davidson invites a comparison between his book and those two, and the only judgment can be that those were worth reading, and his should never have gone to print.
Although Davidson continually asserts that his intention is to write an objective, balanced account of the French Revolution, his real aim is made apparent at the outset by his petulant snipe at Schama and Hibbert. Davidson believes that the Revolution was a catalyst for human progress, the genesis for recognizably modern concepts like democracy, secularism, rule of law, and rationality. This is not an objective account, but rather an attempt to rescue - but not rebut, for Davidson never engages with the theses of those he snipes at - the French Revolution from scholarly accounts that have exposed its fundamentally negative nature. The only use this book has is as an example of how someone's preconceived idea of what a historical event means can lead them to draw conclusions utterly at odds with the evidence before them.
One of Davidson's frequent absurdities is to suggest that the French Revolution brought about rule of law in Europe. This is of course nonsense, as the concept of rule of law was deeply entrenched in European political theory and practice. The Ancien Regime did a much better job of applying rule of law than the Revolutionaries ever managed; even the notorious lettres de cachet represented not a failure of rule of law, but a lack of due process. Davidson appears to confuse the modern ideals of justice, represented in trial by jury, due process, etc, as rule of law; this lack of comprehension is the whole problem with the book. Davidson has heard of various terms, like rule of law, but he doesn't quite understand them. He does admit "it was the Revolutionaries who progressively dismantled, piece by piece, their own system of the rule of law" but maintains nevertheless that somehow this descent into lawless tyranny contributed positively to human progress. Again, this is Davidson's problem: if he was truly engaged with and comprehended the concepts he is writing about, he would be able to see the French Revolution as a deviation from the rule of law.
In the same vein, Davidson repeatedly insists that the French Revolution was peaceful, not violent, even as he chronicles the brutality that infected it from the very beginning. He insists that the Tennis Court Oath is the real representative episode of the Revolution, not the Fall of the Bastille, and therefore the Revolution was peaceful and lawful (or at least orderly). Even accepting this, the Fall of the Bastille occurred less than a month later, and this episode of mob violence involved the murder of prisoners and of the mayor of Paris, and their heads were then proudly paraded around on pikes. This lawless mob violence afflicted the Revolution even past the Thermidorian Reaction that Davidson chooses to delineate its endpoint. Despite the frequent lynchings by lawless mobs, and the tens of thousands judicially murdered, Davidson maintains that the Revolution was inherently peaceful... somehow; he never even attempts to explain this wishful thinking.
In this, Davidson resembles a bit the events he's writing about. Davidson insists that the Revolution was rational, instituting scientific progress and sweeping away the Ancien Regime's superstition. This is, again, complete nonsense; the upper classes of the Ancien Regime participated in scientific endeavors, it didn't take a Revolution to foster scientific progress in France. But frequently one finds that the Revolutionaries were futilely legislating against reality. A typical instance is legislating a fixed exchange rate between paper currency and metal currency, while continuing to print paper currency. Other instances of madness included wage and price controls that worsened hunger and unemployment. And while the Revolutionaries mocked superstitious nuns seeing images of Christ in pieces of fish, the paranoid Revolutionary insistence that every misfortune, especially crop failures, were caused by counter-revolutionaries, is a far more outrageous departure from reason.
And so we reach Davidson's assertion that the Revolution was secular. Virtually the first act of the National Assembly was to require the Catholic clergy to swear an oath to the nation, promulgate its decrees from the pulpit, and forfeit Church property in exchange for a government paycheck. The Revolutionaries sought to co-opt the Catholic Church, and to transform it to serve the perceived needs of the Revolution; later it sought to establish its own Cult of the Supreme Being. Far from secularizing France, separating Church from State, it sought the exact opposite, to establish a national faith totally subordinated to the State. The brutal repression of the Church, both clergy and laity, is hardly a model for secularism. But secularism = good, national church = bad, French Revolution = good, therefore the French Revolution must have been secular. Again, Davidson's conclusions stem from his prejudices, evidence be damned. Davidson is at least honest enough not to pretend the Revolution didn't persecute Catholics, although he often seeks to justify it, and he does elide some major episodes of it.
In the appendices at the end of the book Davidson's ignorance and antipathy for Catholicism is laid bare when he ludicrously asserts that the reason the Revolution did not enact female suffrage was because of France's Catholic culture. This is his excuse for France's failure to enact female suffrage until 1944, and he goes on to say "in even more profoundly Catholic and therefore conservative European countries, it took even longer for women to gain the vote: Italy in 1946, Greece in 1952... Switzerland in 1971..." while claiming that Protestant countries enacted it sooner. A passage more damning of an author's own intellect could hardly be crafted by his enemies: Greece is, after all, Orthodox not Catholic, and Switzerland is majority Protestant not Catholic. Notably, arch-Catholic Ireland and Poland enacted female suffrage as soon as they gained independence in 1918; Catholic majority countries Belgium and Austria enacted it in 1919, Spain and Portugal in 1931 were comparatively laggardly; many of the Catholic Latin-American states enacted it sooner. Of the Protestant European states, Norway 1913, Denmark 1915, Netherlands 1917, Sweden 1921, and the UK 1928. There's no correlation here. Davidson's prejudice rides freely into absurdity.
It would be possible to list every single error of this kind Davidson makes, but the point has been labored already. This is pure propaganda, and poorly argued at that. Davidson would make for an inept high school teacher, it's a tragedy that any publisher trusted this crank enough to put his book into print.