Hardy's Z-function, related to the Riemann zeta-function (s), was originally utilised by G. H. Hardy to show that (s) has infinitely many zeros of the form 1/2+it. It is now amongst the most important functions of analytic number theory, and the Riemann hypothesis, that all complex zeros lie on the line 1/2+it, is perhaps one of the best known and most important open problems in mathematics. Today Hardy's function has many applications; among others it is used for extensive calculations regarding the zeros of (s). This comprehensive account covers many aspects of Z(t), including the...