Landing craft include a wide range of boats employed in amphibious warfare, specifically designed for carrying troops and their equipment and for beaching, unloading, and retracting. They are also used for resupply operations. While most landing craft are carried to the landing area aboard a larger ship, there are some landing vessels that qualify as ships able to travel independently, although usually with slow speed and difficulty in rough seas. For modern warfare, primarily U.S. doctrine is described here, as it is similar to that used by NATO and other allied countries such as Australia.
In modern amphibious warfare, the classic landing craft, which is a flat-bottomed boat suitable for beaching itself, and then dropping a bow ramp or opening bow doors for the troops and equipment to disembark, is obsolete for direct assault. While direct assault on defended beaches was an icon of World War II, the casualties of such frontal attacks, even with the defensive weapons of the time, made the technique less and less attractive.
“The key to successful amphibious operations in the future is the ability to
launch from ’over the horizon.’ Previously, an amphibious force relied on extensive firepower to suppress and destroy enemy defensive positions while the landing force approached the beach at a speed of only six to eight knots. Clearly the firepower possessed by even most Third World military forces would make such an amphibious assault extremely risky. For amphibious operations to succeed in the future, the amphibious force must be able to act faster than the enemy can react.” — "Fundamentals of Force PlanningVol II: Defense Planning Cases" 
See amphibious warfare for the more modern approaches to attacking a defended seacoast, but making the initial penetrations at undefended or minimally defended points.
Landing craft prior to the Second World War
While landing operations go back into history, a systematic doctrine really did not emerge until the Second World War. It is not the scope of this article to discuss the overall problems of amphibious operations before a real doctrine and implementing technologies emerged, but the results, other than small raids, were typified by what could charitably be called fiascoes, such as the Gallipoli Campaign.
Early Second World War landing craft
There were many landing craft designers, but none with more impact than Andrew Higgins (1886-1952), designer of the original Landing craft, vehicle, personnel (LCVP) or "Higgins Boat", Landing craft, personnel (large) (LCPL), Landing Craft Personnel (LCP)s, and landing craft, mechanized (LCM). In 1964, Dwight D. Eisenhower called Higgins "the man who won the war for us".
The LCVP was the prototype for the others, as well as a workhorse on its own. Originally designed for use as a civilian workboat in the shallow waters of south Louisiana, the boat could operate in 18 inches of water, beach itself, and extract from the beach.  With the addition of a bow ramp suitable for unloading troops and light vehicles on the beach, a modification requested by the United States Marine Corps, the wooden boat could deliver 36 infantry, or 12 infantry and a jeep. Over 20,000 were built, and delivered more troops to beaches than any other landing craft of the war.
The Higgins boats broke the gridlock on the ship-to-shore movement. It is impossible to overstate the tactical advantages his craft gave U.S. amphibious commanders in World War II. — Col. Joseph H. Alexander, USMC (Ret)
The LCVP was not perfect. It could not deliver equipment, such as tanks and artillery, heavier than a jeep. It was purely a boat and could not travel beyond the beach.
Evolved landing craft in the Second World War and Korean War
Inadequate information about tides at the Battle of Tarawa caused the true landing craft to stop at coral reefs, and heavily laden Marines had to wade ashore, under heavy fire. Casualties were extreme.
That invasion may have been saved by a new development, the Landing Vehicle Tracked (LVT), which had both a propeller and tank-like tracks, so it could move over the reefs and, if enemy fire permitted, inland from the beach.
Late Second World War and Korean War Landing Craft
The need for larger craft to deliver heavier equipment, such as tanks, resulted in the larger Landing Craft Tank, the oceangoing Landing Ship Tank (LST, irreverently known as Large Slow Target), Landing Craft Medium (LCM) (later versions were designated Landing Craft Mechanized ), etc. Amphibian vehicles continued to evolve, such as the U.S. Army's DUKW.
Some landing craft were modified to give close-in fire support as the troops landed, such as the Landing Ship Medium, Rocket [[LSMR[[, equipped with multiple rocket launchers, or variants of the relatively large Landing Craft Infantry (LCI), in configurations armed with mortars as the LCI(M) or [[LCIM}}, LCI(G) or LCIG autocannon, anti-aircraft artillery, or smoke generators to conceal the landing.
Modern landing craft and ship-to-shore logistics
While there have been improvements in beach landing craft, they are now seen as primarily logistical support craft, landing on an undefended or secured beach.  Current doctrine is to isolate the landing area by vertical envelopment of troops in helicopters or tilt-rotor aircraft, with a next wave, with heavier equipment, in landing vehicles able to operate both in the water and on land. Only after a beach or port is secured to the traditional landing craft, with a greater cargo-carrying capacity, move in.
A fourth category of amphibious craft encompasses ship-to-shore equipment that have no capability to land under fire, including:
- discharge lighters, metal amphibious boats with propellers and wheels, intended to carry troops and cargo from ships to a secured beach area.
- barges: Flat-bed, shallow-draft vessel with no superstructure that is used for the transport of cargo and ships’ stores or for general utility purposes. Barges may or may not be powered; if not, they need to be towed.
- causeways: A craft similar in design to a barge, but longer and narrower, designed to assist in
the discharge and transport of cargo from vessels. They are even less likely to be powered than a barge, but, if the ship is fairly close inland, causeways can be linked to form a floating roadway. Craft in this category are usually carried by prepositioning ships, which use them to unload.
A Landing Craft Utility (LCU), normally carried in the well deck of an amphibious ship, has the capability to operate out of sight of land and the mother ship; it has onboard berthing and messing facilities. Not intended for use in the initial assault, LCUs carry out resupply, possibly among multiple landing sites and a nearby base or ship, as well as removing and redeploying resources.
- Joint Chiefs of Staff (19 September 2001), Joint Publication 3-02: Joint Doctrine for Amphibious Operations
- Higgins Memorial: the Design
- Ships of the U.S. Navy, 1940-1945, LVT -- Landing Vehicle, Tracked and LVT(A) -- Landing Vehicle, Tracked (Armored), ibiblio.org, a project of the University of North Carolina - Chapel Hill
- Joint Chiefs of Staff (5 August 2005), Joint Logistics Over-the-Shore (JLOTS)
- Landing Craft Utility (LCU), Federation of American Scientists