It took Edward d'Eath five months to find what he was looking for. The search was hampered by the fact that he did not know what he was looking for, only that he'd know it when he found it. Edward was a great believer in Destiny. Such people often are.

The Guild library was one of the largest in the city. In certain specialized areas it was the largest. These areas mainly had to do with the regrettable brevity of human life and the means of bringing it about.

Edward spent a lot of time there, often at the top of a ladder, often surrounded by dust.

He read every known work on armaments. He didn't know what he was looking for and he found it in a note in the margin of an otherwise very dull and inaccurate treatise on the ballistics of crossbows. He copied it out, carefully.

Edward spent a lot of time among history books as well. The Assassins' Guild was an association of gentlemen of breeding, and people like that regard the whole of recorded history as a kind of stock book. There were a great many books in the Guild library, and a whole portrait gallery of kings and queens,

It was said later that he came under bad influences at this stage. But the secret of the history of Edward d'Eath was that he came under no outside influences at all, unless you count all those dead kings. He just came under the influence of himself.

That's where people get it wrong. Individuals aren't naturally paid-up members of the human race, except biologically. They need to be bounced around by the Brownian motion of society, which is a mechanism by which human beings constantly remind one another that they are… well… human beings. He was also spiralling inwards, as tends to happen in cases like this.