I'm not sure why you need to deploy the caps lock because you've not explained to me before why these are the relevant series of his career!
Aye, but it's a familiar topic with CWers - the AGAIN was for their benefit.
1989 - he should not have been picked (as shouldn't any number of players that summer), was just a couple of months out of uni, and I generally tend to ignore a couple of early Tests for players of this ilk - premature selections which inevitably backfired involving players who would go on to become excellent. A few other examples are Imran Khan (1971-1974), Andrew Flintoff (1998-2000) and Sachin Tendulkar (1989/90).
1996/97 and 1998/99 - he should never, ever have played these 6 Tests. If you've read his autobiography you'll know why - he describes himself, esssentially, as completely incapable of performance (he could hardly bend his back never mind twist). I think he averaged about 10 in them, over 12 innings. This pulls things out quite a bit. It also means precisely zilch if you're trying to assess Atherton when he was fit to play (which was the vast majority of time). Any time someone tells me that someone with long-term performance behind them had a few games where they played with an injury they shouldn't have, I'm willing to knock it out from their career record.
2001 - by this time, he was on the decline. Most players have a bit of a comedown at the end of their careers (though Atherton was only 33, he'd already been told his time was ticking away by the docs and physios). I generally tend to ignore this for the same reason as the early Tests - I think someone who's been good for ages has the right for a few later games to be taken with no great seriousness. A few other examples of this are Vivian Richards (1989-1991), Ian Botham (1989-1992, nothing earlier), Stephen Waugh (2001/02-2003/04) and Allan Donald (2001/02).
Anyhow what baffles me is his overall career record - how can a player as good as he was have a batting average languishing in the 30s?
For two reasons - the first set are detailed above. Circumstances really did conspire against him.
The second is that perhaps people initially thought he was better than he actually was. Atherton was a very fine Test opener for a long time. But he wasn't someone from the very top of the tree. He was certainly never a Boycott or a Hutton. He was probably never even an Amiss or an Edrich.