Forgeries are documents deliberately contrived to deceive, as distinct from facsimiles, which are generally mechanical copies of real documents. There have always been spurious documents and letters in circulation and it is an unfortunate fact that they appear occasionally as the real thing. Most forgeries should not present a serious problem to an experienced dealer, but it may be useful to have some idea of the sort of material we have to consider. The following examples will show forged documents contrasted with genuine examples, where available, with a few words of explanation. Many of the examples of forgeries come from our own extensive collection. We always welcome any information about doubtful documents especially if accompanied by good quality scans. It is worth adding that everything we sell is guaranteed to be genuine (we do not offer 'certificates of authenticity', which we consider to be worthless). We are widely consulted by collectors, libraries and other dealers on the question of authenticity.