How does this condition code works?

int a,b,c,d, e=11;
a=b=c=d=0;
do{
    e = e+1;
    a = a+1;
    if(a>=2) b = b+1;
    if(b>=2) c = c+1;
    if(c>=2) d = d+1;
    if((a&&b)&&(c&&d)){
        printf(" %d",e);break;
        }
    }while(1); //outputs 15

Didn't really understand the last if statement. What does (a && b) means? Is is and operation?