The concept of a PKI (public key infrastructure) has been around for decades, but it is one strand of IT which has taken an extraordinarily long time to come to fruition within the mainstream. This is mostly because implementing a PKI is time consuming and difficult. Maintaining a PKI is equally time consuming and even more difficult within the real world of mergers and acquisitions against a backdrop of ever-changing technology. Many organisations simply give up and hand everything over to a third party who promises to manage everything on their behalf. This is generally not a good idea and simply delays the inevitability of failures and misunderstood complexity. This book explores all the aspects of implementing and maintaining a PKI that the other books on the subject seem to miss. It reflects decades of hard-won experience, not only in PKI, not only in IT, not only in electronics, but in business, government agencies and academia alike. The book also explores the existence of a PKI alongside other technologies, such as biometrics, and against an ever-changing world of development methodologies. This last point is particularly relevant at this time as we are in the middle of a quiet, but all encompassing revolution in this respect. Consequently, this is the one book on PKI that you have to have on your shelf, whether you be a company director, IT manager, government minister or teacher of IT. It is the book which fills in all the gaps left in the literature and treads paths which others fear to tread. You will enjoy it enormously if you are from an IT background.