Ah, to Have a Half Million Dollars Laying About

Then I might go bid on the only known inscribed copy, apart from the author's own, of the first printing of A Study in Scarlet, the first appearance of Sherlock Holmes.

From the story about the coming auction...

Arthur Conan Doyle, at the time a respected though not particularly successful doctor in his mid-twenties, sold the story and copyright to the publisher, Ward, Lock and Co., for £25 ($37).

There are only three signed or inscribed copies recorded of this monument in the detective genre of literature, one of the rarest and most highly sought books of modern times, (only twenty copies in U.S. and British libraries and merely eleven in private hands) a volume keenly desired by Doyle and/or detective fiction collectors all over the world: the author's copy, currently in the possession of the Estate of Dame Jean Conan Doyle (the author's youngest daughter, who died in 1997); that under notice; and a copy at Yale's Beineke Library. The copy at the Beineke Library, tragically however, was mutilated, its inscribed page excised at some point prior to March 2003, when the crime was discovered. This, then, is one of only two signed or inscribed copies known to exist.