I like to use the S&P cash (symbol $SPX) to trade the S&P futures (symbol ES #F) because of the clarity of the cash. I am aware of the price differences between the cash and the futures due, in part, to the premium. I also am aware that very large traders can move the price levels of both the cash and the futures through buy/sell programs. My question is whether it is a mistake to think of the cash as the dog and the futures as the tail? A second question is whether anyone can direct me to any articles on using the cash to trade the futures?