Total war
Strasser, who was chief commander of German Imperial Navy Zeppelins during World War I, the main force operating German strategic bombing across Europe and the UK, saw bombing of civilians as well as military targets as an essential element of total war. He argued that causing civilian casualties and damaging domestic infrastructure served both as propaganda and as a means of diverting resources from the front line.

We who strike the enemy where his heart beats have been slandered as 'baby killers' ... Nowadays, there is no such animal as a noncombatant. Modern warfare is total warfare.

Propaganda: One of the features of total war in Britain was the use of government propaganda posters to divert all attention to the war on the home front. Posters were used to influence public opinion about what to eat and what occupations to take, and to change the attitude of support towards the war effort. Even music halls were used as propaganda, with propaganda songs aimed at recruitment.
After the failure of the Battle of Neuve Chapelle, the large British offensive in March 1915, the British Commander-in-Chief Field Marshal John French blamed the lack of progress on insufficient and poor-quality artillery shells. This led to the Shell Crisis of 1915 which brought down both the Liberal government and Premiership of H. H. Asquith. He formed a new coalition government dominated by Liberals and appointed David Lloyd George as Minister of Munitions. It was a recognition that the whole economy would have to be geared for war if the Allies were to prevail on the Western Front.
Carl Schmitt, a supporter of Nazi Germany, wrote that total war meant "total politics"—authoritarian domestic policies that imposed direct control of the press and economy. In Schmitt's view the total state, which directs fully the mobilisation of all social and economic resources to war, is antecedent to total war. Scholars consider that the seeds of this total state concept already existed in the German state of World War I, which exercised full control of the press and other aspects economic and social life as espoused in the statement of state ideology known as the "Ideas of 1914".

Rationing: As young men left the farms for the front, domestic food production in Britain and Germany fell. In Britain, the response was to import more food, which was done despite the German introduction of unrestricted submarine warfare, and to introduce rationing. The Royal Navy's blockade of German ports prevented Germany from importing food and hastened German capitulation by creating a food crisis in Germany.
Almost the whole of Europe and some of the European colonial empires mobilised soldiers. Rationing occurred on the home fronts. Bulgaria went so far as to mobilise a quarter of its population, or 800,000 people, a greater share of its population than any other country during the war.

World War II: The Second World War was the quintessential total war of modernity. The level of national mobilisation of resources on all sides of the conflict, the battlespace being contested, the scale of the armies, navies, and air forces raised through conscription, the active targeting of non-combatants (and non-combatant property), the general disregard for collateral damage, and the unrestricted aims of the belligerents marked total war on an unprecedented and unsurpassed, multicontinental scale.

Imperial Japan: During the first part of the Shōwa era, the government of Imperial Japan launched a string of policies to promote a total war effort against China and occidental powers and increase industrial production. Among these were the National Spiritual Mobilization Movement and the Imperial Rule Assistance Association.
The State General Mobilization Law had fifty clauses, which provided for government controls over civilian organisations (including labour unions), nationalisation of strategic industries, price controls and rationing, and nationalised the news media. The laws gave the government the authority to use unlimited budgets to subsidise war production and to compensate manufacturers for losses caused by war-time mobilisation. Eighteen of the fifty articles outlined penalties for violators.
To improve its production, Imperial Japan used millions of slave labourers and pressed more than 18 million people in East Asia into forced labour.

United Kingdom: Before the onset of the Second World War, Great Britain drew on its First World War experience to prepare legislation that would allow immediate mobilisation of the economy for war, should future hostilities break out. Rationing of most goods and services was introduced, not only for consumers but also for manufacturers. This meant that factories manufacturing products that were irrelevant to the war effort had more appropriate tasks imposed. All artificial light was subject to legal blackouts.

..There is another more obvious difference from 1914. The whole of the warring nations are engaged, not only soldiers, but the entire population, men, women and children. The fronts are everywhere to be seen. The trenches are dug in the towns and streets. Every village is fortified. Every road is barred. The front line runs through the factories. The workmen are soldiers with different weapons but the same courage."

Not only were men conscripted into the armed forces from the beginning of the war (something which had not happened until the middle of World War I), but women were also conscripted as Land Girls to aid farmers and the Bevin Boys were conscripted to work down the coal mines.
Enormous casualties were expected in bombing raids, so children were evacuated from London and other cities en masse to the countryside for compulsory billeting in households. In the long term this was one of the most profound and longer-lasting social consequences of the whole war for Britain. This is because it mixed up children with adults of other classes. Not only did the middle and upper classes become familiar with the urban squalor suffered by working class children from the slums, but the children got a chance to see animals and the countryside, often for the first time, and experience rural life.
The use of statistical analysis, by a branch of science which has become known as Operational Research to influence military tactics, was a departure from anything previously attempted. It was a very powerful tool but it further dehumanised war particularly when it suggested strategies that were counter-intuitive. Examples, where statistical analysis directly influenced tactics include the work done by Patrick Blackett's team on the optimum size and speed of convoys and the introduction of bomber streams, by the Royal Air Force to counter the night fighter defences of the Kammhuber Line.

Nazi Germany: In 1935 General Ludendorff in the book Der Totale Krieg gave life to the term "Total War" in the German lexicon. However, being followers of the stab-in-the-back myth, military and Nazi leadership believed that Germany hadn't lost World War I on the battlefield but solely on the home front.
Therefore, Germany started the war under the concept which was later named blitzkrieg. Officially, it did not accept that it was in a total war until Joseph Goebbels' Sportpalast speech of 18 February 1943—in which the crowd was told "Totaler Krieg – Kürzester Krieg" ("Total War – Shortest War”.)

Goebbels and Hitler had spoken in March 1942 about Goebbels' idea to put the entire home front on a war footing. Hitler appeared to accept the concept, but took no action. Goebbels had the support of minister of armaments Albert Speer, economics minister Walther Funk and Robert Ley, head of the German Labour Front, and they pressed Hitler in October 1942 to take action, but Hitler, while outwardly agreeing, continued to dither. Finally, after the holidays in 1942, Hitler sent his powerful personal secretary, Martin Bormann, to discuss the question with Goebbels and Hans Lammers, the head of the Reich Chancellery.  As a result, Bormann told Goebbels to go ahead and draw up a draft of the necessary decree, to be signed in January 1943. Hitler signed the decree on 13 January, almost a year after Goebbels first discussed the concept with him. The decree set up a steering committee consisting of Bormann, Lammers, and General Wilhelm Keitel to oversee the effort, with Goebbels and Speer as advisors; Goebbels had expected to be one of the triumvirate.  Hitler remained aloof from the project, and it was Goebbels and Hermann Göring who gave the "total war" radio address from the Sportspalast the next month, on the 10th anniversary of the Nazi's "seizure of power".

I ask you: Do you want total war? If necessary, do you want a war more total and radical than anything that we can even imagine today?
The commitment to the doctrine of the short war was a continuing handicap for the Germans; neither plans nor state of mind were adjusted to the idea of a long war until the failure of the Operation Barbarossa. A major strategic defeat in the Battle of Moscow forced Speer as armaments minister to nationalise German war production and eliminate the worst inefficiencies.

Canada: In Canada early use of the term concerned whether or not the country was committing enough to mobilising its resources, rather than whether or not to target civilians of the enemy countries.  During the early days of the Second World War, whether or not Canada was committed to a "total war effort" was point of partisan political debate between the governing Liberals and the opposition Conservatives.  The Conservatives elected as their national leader Arthur Meighen, who had been the cabinet minister responsible for implementing conscription during the First World War, and advocated for conscription again.  Prime Minister W.L.