Thousands of encrypted, still undeciphered manuscripts are found in libraries and archives all over Europe. Examples of such material are diplomatic correspondences and intelligence reports, private letters and diaries as well as manuscripts related to secret societies. In the talk, we show some historical ciphers and various methods used to encipher those. We then look at various algorithms to decipher them, and illustrate how modern computational technology with philological methods can be used to decipher an old hand-written manuscript from the mid-eighteenth century, the Copiale cipher. We will describe the book, the features of the text, the method by which we deciphered it and will give a brief description about its content and the society that was hiding behind the cipher. The manuscript is digitized, transcribed, decoded and translated to English, and is available from the Copiale webpage: http://stp.lingfil.uu.se/~bea/copiale. In the end, we will point to future directions f or developing computer-aided tools for automatic and semi-automatic analysis of historical ciphers, thereby creating new insights into our history and contributing to historical cryptology as a flourishing research area.