Well, ShermanSam, you can never have too many references. A good start would be:
Sherman: A History of the American Medium Tank by Hunnicutt. The Bible.
Sherman Firefly by Hayward. The Firefly Bible.
Israeli Sherman by Gannon. The Israeli Bible.
Sherman Walk-Around by Squadron/Signal.
M4 Sherman by George Forty.
Sherman Tank in British Service, Osprey publishing
Osprey Modelling Manual on the Sherman.
I have all of these. In addition, there are other Osprey books on the Sherman and its tank destroyer variants that are recommended. Squadron/Signal also has In Action titles on the Sherman, tank destroyers, and SP artillery pieces. The latter two have vehicles that aren't Sherman based included, as not all of the vehicles of thsoe types were base on a Lee/Grant/Sherman chassis.
And probably more that I'm forgetting right now...
Greg