During his journey through Samburu tribal land, a vast region that covers 8,000 square miles and includes the Samburu National Park, it becomes clear that many of the traditional ways do remain, even among Samburu who have left the tribal homeland to pursue careers in Nairobi and other large cities.'They are incredibly resilient and proud people who have held out [against modernisation],' adds Hook.'The [neighbouring] Masai have moved much closer to everyone else but because the Samburu are further away from the big cities, they've retained their customs a little bit longer.They are extraordinary people.'But while the Samburu form the backbone of Hook's latest African venture, they're by no means the only people he meets during a journey that takes him into one of the continent's newest - and least stable - nations, South Sudan.
I shoot on film so sometimes, people think you're a spy when they can't see the pictures!
'Despite the dangers, Hook says his African journey will continue for as long as there are still people to photograph and new places to explore.
'It's the people you meet,' he says of the pleasures of African travel.
For them, the main threat to their way of life comes not from encroaching technology but from war.'It was very lucky - we just got in and out in the nick of time,' explains Hook of his trip to South Sudan, a country currently convulsed by a vicious civil war that began last December.
'Based on intelligence on the ground, we knew we only had a blip of peace before the whole thing unravelled again.''The main risks, on the whole, are that you can be targeted for some money or caught in the crossfire,' he explains.
'I was apprehensive [about going into South Sudan] but literally you go along and if all's clear you carry on, while keeping an eye on the information that comes to you on the ground.'On the whole, people are immensely hospitable,' he adds.
'But I have had situations in past where I've been arrested or passport taken away by suspicious officials.
After almost 40 years of photographing Africa, Hook is explaining why the dark continent continues to fascinate.
Born and raised in Kenya, he's spent decades charting the changing circumstances of Africa's people, whether Samburu pastoralists or Tanzania's Hadza hunter-gatherers.