WW2
During the second world the only "active" Sweden made, was when we helped Finland in "the Finnish winter war". The war was between Finland and the Soviet Union and lasted between 1939 and 1940. Sweden helped Finland much by sending supplies and volunteer soldiers. The war was very even; although the Finnish soldiers were heavily outnumbered they won almost every battle for the first six months. But when the Soviet soldiers got more reinforcements Finland lost. If Sweden had been more involved in the war, i.e. if we had sent more volunteers, or even engaged openly in the war Finland would have a big chance of winning.
Depression
How the world depression after the First World War affected Sweden
In 1920, Sweden struggles with economical problems along with the rest of the world. Many men had died in the wars, and therefore Sweden was missing labour. Things got better at the end of the 20's. But then, again, a great depression struck Europe, This because of the "Wall Street crash" (USA demanding France and Germany to pay the loan).
Though to the depression, Sweden was a fairly rich country and in the early 30's a unique socialistic idea got majority in the Riksdag (congress). It spoke for shortened time at work, vacation, superannuating and health insurance. Because of this, the distribution of money became much more fair. Sweden stimulated the labour market and that accomplished prosperity in Sweden.