In terms of essays, I would say Oliver Sacks. His breadth of hard knowledge and imagination and empathy seems to constitute the perfect mind to me.

If you get stuck, get away from your desk. Take a walk, take a bath, go to sleep, make a pie, draw, listen to music, meditate, exercise; whatever you do, don't just stick there scowling at the problem. But don't make telephone calls or go to a party; if you do, other people's words will pour in where your lost words should be.

A sea-green sky: lamps blossoming white. This is marginal land: fields of strung wire, of treadless tyres in ditches, fridges dead on their backs, and starving ponies cropping the mud. It is a landscape running with outcasts and escapees, with Afghans, Turks and Kurds: with scapegoats, scarred with bottle and burn marks, limping from the cities with broken ribs. The life forms here are rejects, or anomalies: the cats tipped from speeding cars, and the Heathrow sheep, their fleece clotted with the stench of aviation fuel.

[H]ope takes you by the throat like a stranger, it makes your heart leap.

A statute is written to entrap meaning, a poem to escape it.

[Margaret Thatcher] scorned and despised other women, and predicated her values entirely on the values of her father, a small town shopkeeper.

You think you're writing one historical novel and it turns into three, and I'm quite used to a short story turning into a novel - that's happened through my whole career.