All of these books have two things going for them: they give an idiosyncratic and evocative view of events distant in both time and place and they are really well written. People who have been taught to write grammatically correct English tend to snicker at the Da Vinci Code and other books by Dan Brown: the illiteracy is sometimes enough to stop the flow of the racing narrative because you can't follow who is doing what to whom. When Fermor left England with a copy of Horace as one of two books to carry him across the continent it was in Latin. Before dropping out of his fancy school he had been formally educated in the ancient tongue. That meant that he could recognise a gerund, a subjunctive clause, a preposition or a phrasal verb in either Latin or English. The Horace for a contemporary 18 year old to take Inter-railing round Europe would be more likely Rumpole of the Bailey. I also went to a fancy school but was useless at Latin and I was unable to translate its formality into better writing in English. Having O'Manch staying with us for 4 months learning English as foreign language has been an education for us all. When I was at school I thought all that grammar was just an impediment to the communication; I now realise that grammar is essential for communicating your ideas unambiguously.
I've had occasion to remark about our unconsidered certainties - the background that cannot be seen and so is never questioned: that homosexuality is a kind of curable disease, that it's okay to hit children with sticks, that life is sacred, that boxing is a sport in which civilised people might engage. It would not be true to say that there is a vein of anti-semitism in One's Company - nothing compared to what central Europe was getting geared up to in the 1930s - but casual use of Jewish racial stereotypes (salesmen, clever) has modern readers brought up all standing. Nobody nowadays thinks that a pipe is an essential piece of kit to take to the Brazilian jungle. You will notice this of many books written before WWII. It would be about as true to say that Peter Fleming or Agatha Christie was anti-semitic as to say that the Iona Institute is homophobic or that the driver of the Clapham omnibus (and most of his passengers) is racist. After WWII, of course, in Europe there was rather less point in uttering casual racial stereotypes about Jews because there weren't any.
There's a nice critical tribute by Ben Downing to celebrate Peter Fleming's centenary. And here's an attempt by Robert Ryan to bring him out of eclipse by his younger and ultimately more famous brother Ian '007' Fleming. But forget all that, go and get any of Fleming's books out of the library: real life on the edge trumps fantasy however fantastic.