Editing M4 Sherman (section)

===Doctrine===
[[File:Sherman tank and Horsa glider.jpg|thumb|A Sherman [[DD tank|DD]] amphibious tank of [[13th/18th Royal Hussars]] in action against German troops using crashed [[Airspeed Horsa]] gliders as cover near Ranville, [[Operation Overlord]], Normandy, 10 June 1944]]

As the United States approached entry into World War II, armored employment was doctrinally governed by [[List of United States Army Field Manuals#FM 100-5|Field Manual&nbsp;100–5, Operations]] (published May 1941, the month following selection of the M4 tank's final design). That field manual stated:
{{blockquote|The armored division is organized primarily to perform missions that require great mobility and firepower. It is given decisive missions. It is capable of engaging in all forms of combat, but its primary role is in offensive operations against hostile rear areas.{{sfn|''Field Service Regulations FM&nbsp;100–5, Operations'', 22 May 1941|p=1072}}}}

The M4 was, therefore, not originally intended primarily as an [[Infantry tank|infantry support tank]]. It placed tanks in the "striking echelon" of the armored division and placed the infantry in the "support echelon", without directing that tanks should only seek to attack other tanks, thus leaving target selection up to the field commander based on what types of units were available to him to attack. A field manual covering the use of the Sherman (FM 17–33, "The Tank Battalion, Light and Medium" of September 1942) described fighting enemy tanks, when necessary, as one of the many roles of the Sherman, but devoted only one page of text and four diagrams to tank-versus-tank action out of 142 pages.{{sfn|''Field Service Regulations 17–33, The Tank Battalion, Light and Medium'', 22 May 1941}} This early armored doctrine was heavily influenced by the sweeping early war successes of German [[blitzkrieg]] tactics. By the time M4s reached combat in significant numbers, battlefield demands for infantry support and tank-versus-tank action far outnumbered the occasional opportunities of rear-echelon exploitation.{{citation needed|date=April 2015}}

United States doctrine held that the most critical anti-tank work{{snd}} stopping massed enemy tank attacks{{snd}} was primarily to be done by towed and self-propelled anti-tank guns, operated by [[Tank destroyer battalion (United States)|"Tank Destroyer" battalion]]s, with friendly tanks being used in support if possible.{{sfn|''Field Service Regulations FM&nbsp;100–5, Operations'', 22 May 1941|p=680, 685}} Speed was essential to bring the tank destroyers from the rear to destroy incoming tanks. This doctrine was rarely followed in combat, as it was found to be impractical. Commanders were reluctant to leave tank destroyers in reserve; if they were, it was also easier for an opposing armored force to achieve a breakthrough against an American tank battalion, which would not have all of its anti-tank weapons at the front during the beginning of any attack.{{sfn|Jarymowycz|2009|pp=87-103}}