Tinkers' Weaponry, by Sheriff Bownana, is the fourth book in Tinkers' Construct. It covers the weaponry in Tinkers Construct, the abilities of each weapon and the modifiers that apply. Like Materials and You: Volume 2, it is a book obtained once you have created any one of the four basic blocks (Part Builder, Stencil Table, Tool Station, or Pattern Chest).
Note, this book appears to have been added in 1.7.1.
Should you lose your copy, you can create a new one by crafting Mighty Smelting.
Diary of a Tinker can be crafted from this book.