I don't think that is true any more. Coogan is a good example of the approach De Valera was afraid of : his Collins biography is so pro-Collins that his De Valera one almost had to be hopelessly biased against its subject. I think the Collins book is quite good but I don't recommend the De Valera one. Peter Hart's Mick is also very good and not what people with a crude view of Hart would expect. There isn't a definitive biography of De Valera but Diarmaid Ferriter's Judging Dev is an interesting case for the defence.

Part of the problem is that Collins died at the height of the civil war so he never had time to try really governing. There is a temptation to map our own preferred narrative onto him. De Valera by contrast left a huge, messy legacy that is hard to unpick.

Most historians see Dev as a far more sophisticated figure than he was often portrayed. His handling of the Treaty split was disastrous but he showed remarkable talent to re-enter politics in just four years. He was a brilliant electoral politician and a good minister for foreign affairs. His economic policy was deeply flawed but was the orthodoxy of Irish Republicanism. He was a conservative but had a far more sophisticated relationship with the church than his critics realise. His government did more for the poor than his opponents. Most crucially he navigated Ireland from the Treaty to the 1937 constitution peacefully which is an extraordinary achievement.

By contrast we know Collins was a superb guerrilla leader and a promising administrator. But nearly everything else is speculation.

While we're on the subject, can anyone recommend some books on either the conflicts themselves or biographies of both Collins or de Valera?