Churchill's survival as a warlord was never more greatly tested than in the 30 months between the Battle of Britain and El Alamein. As German forces ruthlessly crushed Europe, and the Japanese seized fortresses in the East, it took an indomitable spirit to rise above these tragic events. Max Hastings has even better words for the British leader in Finest Years (Harper Press, £35), a monumental study of his war years.

Churchill’s follies and failures, claims Hastings, were “pimples upon the mountain of his achievement”.

Hastings is one of the finest military historians writing today, as his previous forays into the Second World War, Armageddon and Nemesis, have shown.

The fascination of this particular appraisal lies in Churchill’s rogue personality, a mixture of aggression, guile and brandy. It was a personal as well as a strategic battle right from the start, as Churchill sought to conquer foes at home and abroad. Hastings emphasises that Britian’s forces and equipment could not compare with those unleashed by Hitler and the nation needed a Churchill to put spine into the population.

Churchill’s support for the SOE to “set Europe ablaze” provided some of the most stunning actions of the war. But, as Hastings critically reveals, they became self-defeating as arms supplied by the Allies were ultimately used against rival nationalist forces, while the Germans indulged in reprisals.

But perhaps the most intriguing — one might say dangerous — aspect of Churchill’s vision was the appropriately coded Operation Unthinkable in which 47 Allied divisions, together with Wehrmacht soldiers, would attack the Russians in order to relieve Poland. Mercifully, this campaign did not get beyond the planning stage, inevitably to the chagrin of the Poles, who were to suffer so severely under the Communists. It does, however, reveal the extraordinary compass of Churchill’s mind, which pursued both the real and the radical in the war with ferocious zeal.

Forgotten wars often make the best books and Colin Smith’s England’s Last War Against France (Weidenfeld and Nicolson, £25) is a classic on the conflict with Hitler’s Vichy allies under Marshal Petain, the hero of Verdun in the Great War. Highly controversial, too, showing Churchill’s determination to carry the war to the enemy, whoever it might be. The attack on the Oran naval base in Algeria in which 1,300 French sailors were killed has left a legacy that still rankles in France.

Smith looks at anti-Vichy crusades that range from Syria to Madagascar and on to North Africa. They make for a superb book on an astonishing array of long-buried incidents. One of its provocations is that so many French soldiers who were rescued at Dunkirk deserted the British when they were needed most. But a distaste for de Gaulle and a belief that Germany would win the war led them into a desperate series of actions against the British, evoking the historic heritage of Trafalgar and Agincourt. The crucial question as to why Germany did not win the war is probed deeply by Andrew Roberts in The Storm of War (Allan Lane, £25). He is unsparing in his analysis of Hitler’s naive command decisions which doomed the Third Reich. He claims that instead of invading Russia (Operation Barbarossa), the Nazis should have applied all their military power to North Africa, opening the way to the oil fields of Iran and Iraq and sweeping into India. Alternatively, if Berlin, Rome and Tokyo had co-ordinated their efforts in destroying Russia instead of attacking America they would not have been engaged in the two-front war that materlialised.

Finally, Hitler’s obsession with a pure Aryan race undermined Germany’s resolve in the wider strategy of war. Roberts offers an enthralling debate on the consequences of Hitler’s folly.