I recently also read the memoirs of John Julius Norwich, the son of the diarist here. Try doing the same. As to these diaries, which cover the period 1915 to 1951, they do have historical importance. Duff Cooper (later elevated to 1st Baron Norwich not long before his death in 1954) was a leading supporter of Winston Churchill and his pro-war group of the 1930's, though I fancy that Cooper was a lot less in favour of fomenting war with Germany than was Churchill.
The author, though born in Victorian fin de siecle times (1890), was really an Edwardian, a moneyed homme d'affaires in both senses, a pleasurer of other mens' wives, a gambler and heavy drinker, somewhat of a dilletante, but also with a careerist edge. He left the foreign Office in 1917 to volunteer, belatedly, for the front line in the First World War and served as a very junior officer (2nd Lt.) in the Grenadier Guards. I was struck by the opulence of the officers' dinners (on occasion, seven courses --!-- including salmon, caviar, superb claret etc...), but that was only part of the story. Cooper won a D.S.O. for singlehandedly capturing 18 German infantrymen, he armed only with a pistol. He nearly got the V.C. for that feat.
In the 1920's, having married (against stiff opposition from her father), Lady Diana Mannners, a daughter of the starchy Duke of Rutland, Cooper entered Parliament and stayed there for most of his life. By 1935 he was Secretary of State for War. A photo shows him looking old even then, at 45, no doubt owing to his dissipated way of life. Churchilll kept him on for a while as a minister during WW2, but he was not really up to it and was made a travelling envoy and, after WW2, Amabassador in Paris.
What amazed me, reading these diaries, was how self-centred they are. Little is said of the Russian Revolution and Bolshevism. The rise of Hitler and National Socialism is likewise treated only en passant, despite Cooper's many Jewish connections. He does note that Germany in 1939 seemed far more content and prosperous than the UK. There is a lot more in these Diaries about his food and drink input than about large-scale political events. Perhaps it is unsurprising that Churchill struggled to find a slot sufficiently lightweight for Cooper.
I was surprised, or perhaps put better, not surprised, to find that in these long diaries (as in the memoirs and diaries of others (Colville, Churchill et al)directly involved at high levels of the British and other sides in the Second World War, there is nothing at all about the "gas chambers" within Reich territory, which so many people today regard as being a definite historical fact (though the "narrative" is not so well established and there are persistent attempts to make doubting of it a crime, no less!; really accepted historical fact does not need to be buttressed by the criminal law).
Ultimately, after reading through these diaries, one thinks of Duff Cooper as a self-satisfied nobody briefly elevated to the status of VIP somebody.
Worth reading.