To commemorate the centenary of Turing's birth, this republication of his mother's biography contains a new foreword by Martin Davis and a never-before-published memoir by Alan's brother. The contrast between this memoir and the original biography sheds new light on Turing's relationship with his family, and on the man himself.

Turing's reputation has grown, as his contributions to logic, mathematics, computing, and artificial intelligence have become better appreciated. This republication of his mother's biography is enriched by a never-before-published memoir by Alan's older brother.

'? the readers of the new edition can benefit from a previously unpublished memoir by Alan's older brother John, as well as a new foreword by Martin Davis; both texts provide a different view of Alan Turing, and represent a nice complement to the main part of the book.' Antonin Slavik, Zentralblatt MATH