MacLean was the son of a minister, and learned English as his second language after his mother tongue, Scottish Gaelic. He was born in Glasgow but spent much of his childhood and youth in Daviot, ten miles south of Inverness. He was the third of four sons and had no sisters.

He joined the Royal Navy in 1941, serving in World War II with the ranks of Ordinary Seaman, Able Seaman, and Leading Torpedo Operator. He was first assigned to PS Bournemouth Queen, a converted excursion ship fitting for anti-aircraft guns, on duty off the coasts of England and Scotland. From 1943, he served on HMS Royalist, a Dido-class light cruiser. On Royalist he saw action in 1943 in the Atlantic theatre, on two Arctic convoys and escorting carrier groups in operations against Tirpitz and other targets off the Norwegian coast. In 1944 he served in the Mediterranean theatre, as part of the invasion of southern France and in helping to sink blockade runners off Crete and bombard Milos in the Aegean. During this time MacLean may have been injured in a gunnery practice accident. In 1945, in the Far East theatre, he saw action escorting carrier groups in operations against Japanese targets in Burma, Malaya, and Sumatra. MacLean's late-in-life claims that he was captured by the Japanese and tortured have been dismissed by both his son and his biographer as drunken ravings. * Webster, Jack. Alistair MacLean: A Life. Chapmans Publishers, 1991. ISBN 1-85592-519-2. P191 (Alternate title: Alistair MacLean: A Biography of a Master Storyteller.)) After the Japanese surrender, Royalist helped evacuate liberated POWs from Changi Prison in Singapore.

MacLean was released from the Royal Navy in 1946. He then studied English at the University of Glasgow, graduating in 1953, and then worked as a school teacher in Rutherglen.

While a university student, MacLean began writing short stories for extra income, winning a competition in 1954 with the maritime story "Dileas". The publishing company Collins asked him for a novel and he responded with HMS Ulysses, based on his own war experiences, as well as credited insight from his brother Ian, a Master Mariner. The novel was a great success and MacLean was soon able to devote himself entirely to writing war stories, spy stories and other adventures.

In the early 1960s, MacLean published two novels under the pseudonym "Ian Stuart" in order to prove that the popularity of his books was due to their content rather than his name on the cover. They sold well, but MacLean made no attempt to change his writing style and his fans may easily have recognized him behind the Scottish pseudonym. MacLean's books eventually sold so well that he moved to Switzerland as a tax exile. From 1963–1966, he took a hiatus from writing to run a hotel business in England.

MacLean's later books were not as well received as the earlier ones and, in an attempt to keep his stories in keeping with the time, he sometimes lapsed into overly improbable plots. He also struggled constantly with alcoholism, which eventually brought about his death in Munich in 1987. He is buried a few yards from Richard Burton in Céligny, Switzerland. He was married twice and had three sons with his first wife; the third son was adopted.

MacLean was awarded a Doctor of Letters by the University of Glasgow in 1983.

Compared to other thriller writers of the time, such as Ian Fleming, MacLean's books are exceptional in one way at least: they have an absence of sex and most are short on romance because MacLean thought that such diversions merely serve to slow down the action. Nor do the MacLean books resemble the more recent techno-thriller approach. Instead, he lets little hinder the flow of events in his books, making his heroes fight against seemingly unbeatable odds and often pushing them to the limits of their physical and mental endurance. MacLean's heroes are usually calm, cynical men entirely devoted to their work and often carrying some kind of secret knowledge. A characteristic twist is that one of the hero's closest companions turns out a traitor.

Nature, especially the sea and the Arctic north, plays an important part in MacLean's stories, and he used a variety of exotic parts of the world as settings to his books. Only one of them, When Eight Bells Toll, is set in his native Scotland. MacLean's best books are often those in which he was able to make use of his own direct knowledge of warfare and seafare, such as HMS Ulysses which is now considered a classic of naval fiction.

Stylistically, MacLean's novels can be broken down into four periods:

1. HMS Ulysses through to The Last Frontier. These featured third-person narratives and a somewhat epic tone, and were mostly set during World War II. The Last Frontier contained overt philosophical and moral themes that were not well received. MacLean then switched gears to —
2. Night Without End through to Ice Station Zebra. These all featured first person (and sometimes unreliable) narration laced with a dry, sardonic, self-deprecating humour, and were all set in contemporary times. These are MacLean's most intensely plotted tales, masterfully blending thriller and detective elements. MacLean then retired from writing for three years, returning with —
3. When Eight Bells Toll through to Bear Island, a varied collection that still maintained a generally high quality, with some books harking back to each of the first two periods but usually taking a more cinematic approach (not surprising since he began writing screenplays during this time).
4. The Way to Dusty Death to the end. There were no more first-person stories, and his prose is thought to have often sagged, with excessive dialogue, lazily described scenes, and under-developed characters. All the books sold reasonably well, but MacLean never regained his classic form.

Certain themes are repeated in virtually all of MacLean's novels. For example, they typically feature a male character who is depicted as physically and morally indestructible (for instance, Carrington in HMS Ulysses; Andrea in The Guns of Navarone); such characters are also often described as having an almost inhuman tolerance for alcohol consumption (for instance, the Count in The Last Frontier; Jablonsky in Fear is the Key). Other minor traits or actions also turn up in every book, such as the cliche of characters shaking their heads in order to come to their senses after receiving a blow to the head. "Mediterranean" or Latin American characters are almost always depicted as criminals (as with Gregori in The Satan Bug, Miguel and Tony Carreras in The Golden Rendezvous, and so forth).

Altogether, MacLean published 28 novels and a collection of short stories, as well as books about T. E. Lawrence and James Cook.

MacLean also wrote screenplays, some of them based on his novels and others later novelized by other writers. Around 1980, he was commissioned by an American movie production company to write a series of story outlines to be subsequently produced as movies. He invented the fictitious United Nations Anti-Crime Organization (UNACO), and the books were later completed by others. Among these are Hostage Tower by John Denis and Death Train by Alastair MacNeill. Some of these works bear little resemblance to MacLean's style, especially in their use of gratuitous sex and violence.

Many of MacLean's novels were made into films, but none completely captured the level of detail and the intensity of his writing style as exemplified in classics such as Fear is the Key; the two most artistically and commercially successful film adaptations were The Guns of Navarone and Where Eagles Dare.

After his death, the popularity of his work saw a decline, and, according to Amazon.com, as of 2006 none of his novels are in print in the U.S. However, most are currently still in print in paperback in the UK.

Alistair MacLeanAlistair MacLeanAlistair MacLeanAlistair MacLeanAlistair MacLeanAlistair MacLeanAlistair MacLean?????? ????????????? ??????Alistair MacLean???????????Alistair MacLeanAlistair MacLeanAlistair MacLeanAlistair MacLean??????, ???????Alistair MacLeanAlistair MacLean