Don McCullin- 'Open Skies'
Josef Koudelka- 'Chaos'
Robert Adams- 'Cottonwoods', 'West From The Columbia' etc
Ray Metzker- 'landscapes'
Harry Callahan-the retrospective ed by Sarah Greenough is a good starting point
Mario Giacomelli-'Photographs'-the Italian Bill Brandt
Minor White-The Eye That Shapes
Gabriele Basilico
John Davies
Mark Power-last 3 for more industrial and urban landscapes