Hellmuth Kneser (1898-1973) is the second of three mathematicians from consecutive generations of the Kneser family, all of them with groundbreaking mathematical contributions on a wide range of topics. It was only in recent times that mathematicians recognized how Hellmuth Kneser's work influenced the course of topology and the theory of several complex variables in the 20th century. Indeed he was a mathematician of extraordinarily broad vision and insight and thus contributed to many mathematical fields of pure and applied mathematics including foundations, differential equations,...