Los Angeles, May 16 (DPA) In the world of Indiana Jones, things may have been tough, but at least they were simple. The good guys were good, and the bad guys were so bad that you didn't even need to use criminal profiling to uncover them.

Mix that essential conflict with some swashbuckling action, nail-biting suspense and a heavy dose of the occult and you have the basic structure of the movies - or anyone of the innumerable Saturday cinema matinees of the 1930s on which the entire Indiana Jones shebang rests.

From the beginning, the series was motivated by nostalgia. Creator George Lucas wanted to hark back to those 1930's B-Movies - which he had only seen on TV growing up in the 1960s.

'I began thinking it'd be a good idea to have an archaeologist in a 1930s-style serial - the big shift would be that he was a grave robber who actually finds supernatural artefacts,' said Lucas in the book, 'The Complete Making of Indiana Jones'.

The plan worked brilliantly. 'Raiders of the Lost Ark' was released in 1981, soon after Ronald Reagan took office and tried steering America back to its traditional swagger with an appeal to old fashioned values. The movie earned almost $400 million at the box-office and was followed years later by the 'Temple of Doom' in 1984, and the 'Last Crusade' in 1989.

Almost 20 years later, those original Indy fans are expected to flock back to revisit their childhood hero - and probably take their kids with them.

'People who were kids when that movie first came out are going to watch it nostalgic for the good old days when they saw the first movie,' says Robert Thompson, who heads the Bleier Center for Television and Popular Culture at the Syracuse University.

'My feeling is that Indiana Jones now represents to many of us a moment of national confidence and relative safety, especially for those who were kids in the early '80s and who are now raising kids,'

Anthony Pomes, a marketing director, told the Arizona Republic. 'The terror of 9/11 was 20 years away from those of us who went to see 'Raiders' (of the Lost Ark), and it feels so marvellous to have Indy back with us again.'

'Indiana Jones...makes the good-and-bad-guys equation quicker, neater, easier to read,' added Gerry Molyneaux, professor of film studies at La Salle University in Philadelphia.

'Both the film and the hero compact the qualities and characteristics, that America would like to believe, describe their country and themselves. Indy, the heartland hero, exudes ... earthy style, modest charisma, energy, physical prowess and a combination of brainy cleverness and pragmatic smarts.'