I've been researching Victorian tailoring and am working on drafting my own patterns.
These are the books I'm using.
The Victorian Tailor by Jason Maclochlainn is from my own collection. It's a great general guide for period tailoring.
Men's Garments 1830-1900 by R.I. Davis is a reference book from the library. Since it's the only copy in the Vancouver library system, I was able to sign it out for one week. It's a great reference for pattern drafting. I find the patterns very easy to draft and the instructions are easy to follow.
The Complete Guide to Practical Cutting by Edward Minister & Son is an interesting book to look through, although I didn't use it for any of my current projects. It has really good information on regulations for 1850's military uniforms.