What is the correct CV?

What is the correct way of writing up your CV.? Every time I write up a CV someone tells me is wrong, some say it has too much info, that employers can’t be bothered to read all your CV especially when they get hundreds at a time. Now my latest adviser has brought up a complete new system where I practically have to fill up all 2 pages explaining each point I have given in immense detail even why I have gaps in between the years. Is this really necessary? Don’t employers want a simple but presentable CV rather than my autobiography? What is the correct way of writing up a CV?