Bernard Law Montgomery was born on 17 November 1887 in London. He was educated at St Paul's School and the Royal Military Academy, Sandhurst, and commissioned into the Royal Warwickshire Regiment in 1908. He was severely wounded early in World War One and spent the rest of war as a staff officer.
Between the wars he served in India, Egypt and Palestine. In April 1939, he was given command of the Third Division, part of the British Expeditionary Force which took part in the fighting preceding the Fall of France in June 1940. On his return to England, he was made commander in chief of the "Home Division" - that is, London and the South East. Over the following two years, he focused on training British soldiers to high levels of fitness and co-operation between arms of service. A necessary consequence of this was that he was the General nearest to Winston Churchill, and therefore the senior officer to whom the Prime Minister turned when he needed to speak to a general. Montgomery was savvy and unscrupulous enough to play this to his advantage, ensuring he remained close to the confidences of Churchill in a way denied to other generals not so fortunate in their postings. Well, that's one interpretation (there can be no denying that he was a shameless self-promoter; the only question is whether he was as good as he thought he was). The others are that his competence and skills were evident and that it actually hurt his prospects being seen as a political suckup, since he did not get any frontline assignments for the next 2.5 years, and when he did finally get it, it was due to a plane crash of the guy selected before him.
In August 1942, he was appointed commander of the Eighth Army, the British and Commonwealth forces fighting in the Western Desert (as a result of a plane crash mentioned above). He inspired a dispirited and defeated force to victory over the Germans and Italians at the Battle of El Alamein. Prime Minister Winston Churchill was convinced this battle marked the turning point of the war. Given his numerical advantages, dug-in positions, and terrain that prohibited the Germans from flanking him, it was a battle that would have been tough to lose, but one of the most underrated effects Montgomery had at Alamein was on morale. His troops were tired, had gotten used to losing, and were coming off a long retreat and most of them expected to be pushed out of Egypt entirely by Erwin Rommel's (who had a big psychological edge on Montgomery's predecessors) next offensive. He made it quite clear that he wasn't going to be losing any ground and that he had arrived to stop the Germans and throw them off the continent entirely, and morale soared as he toured the front lines.
Montgomery commanded the Eighth Army in the subsequent Allied campaigns in Sicily and then on the Italian mainland. He was then recalled to the UK to take part in the planning of Operation Overlord, the invasion of Normandy. This, perhaps more than El Alamein, is perhaps Montgomery's most successful act during the war. To be in charge planning the entire Overlord amphibious operation, work out the logistics and organisations behind the largest amphibious landing in history and even to be part of bringing everything ruthlessly into place while politicians bickered over who did what cannot be understated. It may not be the most glorious post, but was absolutely crucial and many have speculated (Max Hastings in his history books predominantly) that there were very few people who could have performed such a duty. His work got Operation Overlord off the ground, yet he receives almost no credit in history for his role in that. This, perhaps, may have been one of the reasons fueling his bitterness, especially with the Americans attaining so much historical glory from Omaha; ironic for two reasons, since Omaha was almost an unmitigated disaster due to the inexperience of some of the attacking U.S Troops (for which Montgomery cannot be blamed) and also due to the fact that Allied intelligence had failed to realise that the Americans would be landing almost on top of a crack German division (which Montgomery most definitely can be blamed for)
During the Normandy landings and for several months afterwards, Montgomery commanded all Allied troops in France. In September 1944, this command was taken over by US general Dwight D. Eisenhower, with Montgomery reverting to command of 21st Army Group. Historians agree that this was the best choice, as the humble and soft-spoken Eisenhower didn't need to be a military genius, as he was a peerless mediator who could make everyone work together (Monty's was hardly the only problematic ego in play) and was very talented at getting his subordinates (including Montgomery) to maximize their own strengths. Ike also valued his subordinates' advice, including Monty's, delegated without micromanaging, and wasn't especially concerned with making himself look good. Montgomery bitterly resented this appointment (Churchill himself approved of Eisenhower as Supreme Allied Commander for all of the listed reasons) although he was promoted to Field Marshal by way of compensation. This and other factors may have led him to authorise the completely uncharacteristic Operation Market Garden - the airborne operation around Arnhem later filmed as A Bridge Too Far. In general, Monty preferred a slower and careful pace to set things up right and proper while the Americans were intent to more aggressively push. The debate as to which approach was correct is, rather normally for historical debates, impossible to answer. The British had not the manpower to expend in the ways the Americans wanted to in surging actions and had to husband their resources carefully, with Monty's approach reflecting this. Unfortunately, his approach differed greatly to the enthusiastic American Generals, leading to the aforementioned disagreements. In any case, Market-Garden was an unmitigated disaster that resulted in horrific casualties for the British, American, and Free Polish forces involved, and utterly failed to open a route across the Rhine into Germany. Montgomery's response was to announce that the most important objectives had been met and that the operation was successful (compare to Eisenhower, who on the eve of the Normandy landings prepared a speech to be read in the event of disaster that would not only admit the failure but also publicly declare all responsibility for it to be his and his alone). Another thing to note is that, especially in the early stages of the combined UK-US involvement in the war, his reputation-building worked on the Germans too - in Sicily, for instance, Germany diverted most of her forces to the east of the island to resist Montgomery's advance and cover their own withdrawal, thus enabling Patton's more glamorous but rather less effectual westward dash to Palermo. Then again, Montgomery made it easy for them by focusing his whole advance on one or two roads at a time, while Patton was much more unpredictable.
It must, however, be remembered that while Monty's forces were moving the slowest of all the Normandy fronts, they were taking on by far the hardest objective and facing the most well equipped and experienced German Divisions in the entire theatre. Once they broke out, Montgomery actually covered more ground facing greater number of troops than the Americans.
Montgomery's later unfortunate assertion that he had saved the Americans in the Battle of the Bulge was controversial to say the least, as it seemed to be insulting to the US Army, who had put in virtually all the blood, sweat and suffering, well at least in the early days. It is true that Eisenhower had asked Montgomery to stabilise the northern front in the Ardennes and make contingency plans for the use of British troops to replace exhausted American units, and that Montgomery had temporarily been placed in charge of some American units North of the "bulge" because otherwise their commander on the South of the "bulge" would have had great difficulty communicating with them. Montgomery did this with great success, even employing great diplomacy in dealings with American units placed temporarily under his command, and is credited with turning a number of isolated delaying and holding actions into a concerted battle by quickly establishing proper organization between many subordinate American commanders who were actually running their own units well but had no knowledge of the bigger picture. But the worst of the Bulge fighting petered out long before any great British involvement needed to be made. Quite rightly, the Americans were greatly offended by his bombastic suggestion that he had won their battle. Amid mounting criticism and a threat to sack him, Montgomery made a humiliating climb-down. It should be pointed out however, that many of Montgomery's criticims were more or less justified, U.S Generals had mishandled the first phases of the operations, being completely surprised and unprepared in what had been a quiet section of the line and it had been Monty who had led to the stabilization of the north side of the Bulge. On the other hand, those exhausted and understrength units had been placed there precisely because it was a quiet section of the line where nobody expected major action. In any event, it was Patton who relieved Bastogne and turned the German flank, and overcame a more complex problem in order to do it—not that Monty's role was easy or unimportant. And, while the remarks were read as insulting the entire U.S Army, Montgomery actually had nothing but praise for the U.S soldier (which meant that he was in a distinct minority amongst Allied Generals, who usually saw the Americans as being soft and pampered and were loathe to give GIs any credit).
Montgomery led his army group in the battle for Germany and, on 4 May 1945, he received the surrender of the German northern armies at Luumlneburg Heath. In victory he was not magnanimous. He haughtily refused a German field-marshal's pleas to allow German civilians to move to safety behind the British front line, on the grounds that he doubted the Germans would have treated British civilians with consideration had they invaded in 1940 (probably not an unfair assessment all in all). The German civilians needed to know their country had lost, and could therefore take their chances with the Russians, and like it.
After the war, Montgomery was created a Knight of the Garter and Viscount Montgomery of Alamein. He commanded the British Army of the Rhine and served as chief of the Imperial General Staff from 1946 to 1948. From 1948 to 1951, he was chairman of the permanent defence organisation of the Western European Union. In 1951, he became deputy commander of the Supreme Headquarters of NATO, serving for seven years. He died on 24 March 1976.
He is also the origin of half of one of the most famous quotes of all time, from The Princess Bride, commenting on Vietnam, "The U.S. has broken the second rule of war. That is, dont go fighting with your land army on the mainland of Asia."
The first rule, he said, "is dont march on Moscow," before adding with characteristic lack of modesty, "I developed these two rules myself."
Only a few Field-Marshals were created during WW2 by the British War Cabinet. Another prominent one was the man regarded by many as Britain's very best fighting general of the war. Field Marshal William Slim (who did not, as was rumored, rise from the ranks) was also in the Warwicks during WWI, and commanded an Indian division during the early part of the North African war, participating in recapturing East Africa from the Italians as well as in the even lesser-known Syrian, Iraqi and Persian campaigns. Slim was sent to command in Burma in 1942, and led the bulk of the British Army out of Burma into India on its longest retreat, saving the bulk of that Army to fight again. In 1944 Slim worked with General Stillwell of the US Army (commanding Kuomintang troops - it's complicated) to defeat the Japanese invasion of The Raj at Imphal, destroying an army group and chasing its remnants out of Burma in a mad race against the impending Monsoon season. As a Field Marshal, he was poised to retake Malaya when the bombs dropped and the war ended. It is tempting to wonder how things might have played out if Slim had commanded the army in Europe and Montgomery had been sent East to deal with the Japanese. A more prudent British government might have done this: Slim got on well with the Americans and was decorated by them in recognition of his achievements. Montgomery's methodical approach might have worked better against the Japanese, and besides there were very few Americans for him to offend in South-East Asia, and Stillwell was an Anglophile who probably wouldnt have been offended anyway. Slim became CIGS immediately after Montgomery.
He ended at #88 in 100 Greatest Britons.