Here is a short list of modern books containing original primary source material - thus historical teachings from a given Fechtbuch (fencing/fight-book) - plus transcriptions and translations. Every book on this page contains English translations, so you do not need knowledge of German in order to read them (although that can be helpful).
Secrets of German Medieval Swordsmanship: Sigmund Ringeck's Commentaries on Liechtenauer
Readers have received this book very well. It contains English translations of Ringeck's texts and an interpretation of these texts by the author. About half the book covers fighting with the longsword (Langschwert), the other material is about sword & buckler, wrestling, etc.
Codex Wallerstein: A Medieval Fighting Book from the Fifteenth Century on the Longsword, Falchion, Dagger, and Wrestling
This book contains transcription of the original Middle High German text as well as New High German and Modern English translations. It covers all the weapons stated in its lengthy title, plus some armoured fighting. It authors also offer a contextual historical analysis of the manuscript.
Polearms Of Paulus Hector Mair
This book is about polearms: spear, long staff and short staff, halberd and poleaxe, plus mismatched weapons. Each page shows a pictured technique simultaneously explained in Latin, German and English. This is a pure source-book, so you must interpret moves for yourself.
Arte Gladiatoria Dimicandi: 15th Century Swordsmanship of Master Fillipo Vadi
A very pretty book of techniques for unarmored longsword, armored poleaxe and estoc, spear, wrestling and oddities. Its authors provide transcription and translation plus an exposition of the culture in which the manuscript was produced.
Medieval Combat: A Fifteenth-Century Illustrated Manual of Swordfighting and Close-Quarter Combat
This book has been around for while, and has proven to be a perennial favorite. It presents the dynamic last edition fight-book by Talhoffer (1467) which covers longsword (unarmored and armored), poleaxe, dueling pavises, dagger, wrestling, falchion, sword & buckler, and even some horsemanship. Its unusually attractive artwork yet very sparse uncommented captions make it something of an advanced compendium rather than a basic manual. The author also provides historical background for that master, and explanations of the weaponry in context of judicial dueling.