I like A History of the Popes by John W. O'Malley, S.J. for a brief overview of the papacy. It is from a Catholic viewpoint (the S.J. signifies that the author is a Jesuit), but it doesn't give a complete whitewash of scandals and corruption during the institution's history. It's relatively easy to read and relatively cheap (which also means it's fairly readily available in libraries.

As for a lack of bias, I have no idea what kind of person could provide that. It is fairly difficult to find someone that has no bias whatsoever regarding Catholicism, given its history and how widely it has spread as an ideology. As with most things in history, the best defense against bias is reading a multitude of sources so you can find the big historiographical trends. In such a topic as the two thousand years of Catholic Church history, that would require a whole lot of reading--certainly more than one book.