If then logic with && ||

Can someone explain to me or point me to documentation as to why the following function doesn't work?

var x = 1;
var y = 2;
var z = 1;

function logicTest() {
    if ((x && y && z) === 1 ) {
        return true;
    } else {
        return false;
    }
}

I know that I can type it out the long way as follows:

function logicTest() {
    if (x === 1 && y === 1 && z === 1 ) {
        return true;
    } else {
        return false;
    }
}

But I'm really trying to understand why the first doesn't work and also if there is a better way of typing the second if/then statement or if that is just the way it will always have to be.

Thanks!