Richard Hollis has a nice piece in the Guardian UK on Jan Tschichold. Though probably best known for his reworking of the design of Penguin paperbacks Tschichold was at the forefront of the new typography movement of the late 1920’s.
Slideshow from the Guardian article
Jan Tschichold at Wikipedia
Also of note: Thames & Hudson’s recently published Jan Tschichold – Master Typographer: His Life, Work and Legacy