Two books, scheduled for publication during the Trades Union Congress and Labour Party conferences this autumn, offer conflicting views of the decline within a decade of a leader who took control of the most powerful union in Britain.
Seumas Milne, labour correspondent of the Guardian, concludes in The Enemy Within that the National Union of Mineworkers has been reduced to its present divided and impotent state by a conspiracy.
Mr Milne, who has described his book as a whodunnit, will claim that Conservative ministers used the security services to sabotage the 1984-85 miners' strike and infiltrate the union's national executive committee to thwart its freedom of action. The Government then manipulated energy policy grotesquely to ensure contraction of coal-mining and NUM power, he claims.
Mr Scargill, a proud Yorkshire proletarian, has co-operated with Mr Milne, son of Alasdair, the former director-general of the BBC.
But Paul Routledge, a former labour editor of the Times who is also proud of his Yorkshire proletarian roots, has met tight-lipped resistance to his biography, suitably titled Scargill: The Unauthorized Biography. The NUM president refused him an interview, and so did members of the small circle of ageing activists still loyal to Mr Scargill; others, once close, have been candid and damning.
Fearful anticipation of what they might say was rumoured to have led Mr Scargill to encourage Mr Milne's book, to limit damage threatened by the Routledge researches. The rivalry between a pro-Scargill scion of the Establishment and an anti-Scargill, determinedly unsophisticated Yorkshire nationalist has delighted the labour movement.
Mr Milne, who dug into the story from the Scargillite left, began his book several months before Mr Routledge, from a more sceptical starting point on the left, foresaw a conclusive round of pit closures and decided that the time was ripe for a full biography.
It will run from cradle to political grave. At the TUC and Labour conferences, Mr Scargill can expect to be marginalised by unambiguous condemnation of his leadership of the NUM, which has shrunk to a membership of around 15,000.
Mr Routledge believes many sources were unwilling to speak to him either under persuasion from Mr Scargill or because of the 'extraordinary' loyalty felt to the NUM. 'The argument goes: an attack on Arthur Scargill is an attack on the union which is an attack on you.
'Arthur plays on the loyalty of the men. He's traded on it shamelessly over the years, and when you come close to a man like that, it is a voyage of disillusion.'
Mr Routledge and Mr Scargill once enjoyed 'a sensible professional relationship, as close as any in his days as Yorkshire NUM president'. But a schism opened during the strike; Mr Routledge does not know why.
Mr Milne has told friends that only Roger Windsor, the former NUM official who later accused Mr Scargill of maladministration, refused him an interview. The NUM president gave one.
It is expected to endorse 'some spooky things' Mr Milne discovered about the activities of GCHQ, MI5, and those who have criticised Mr Scargill in newspaper and television disclosures.
Mr Routledge, using erstwhile private archives and some 60 interviews, has a less conspiratorial explanation of the NUM president: 'Forget politics - he's a spoiled brat.'