The Small Unit Tactics SMARTbook, 2nd Rev. Ed.

This handy-sized guide will let you understand the doctrine, concepts, and priorities that drive the way modern small units fight, and then it explains the actual conduct of Small Unit Tactics (SUT).  Learn how leaders employ their soldiers to achieve rapid, decisive victory, complete with reference citations to military Field Manuals (FMs) and publications. 

US Army Special Forces Small Unit Tactics Handbook

Written by veteran SF soldiers and trainers, this book contains a wealth of history, distilled knowledge, and lessons-learned.  Despite the official-sounding title, it is an original work.  While some of the included info is certainly timelessly fundamental, do not confuse this book with others that are simply photocopies of obsolete 50 year old Field Manuals (FM).

Principles of Personal Defense

This short book , better described as a long essay, by the legendary Jeff Cooper, concisely enumerates the necessary traits for success in the hostile defensive environment.  It's a great read for everyone, from those new to concealed carry, to a veteran infantryman.

Contact! A Tactical Manual for Post Collapse Survival

This book does a great job taking military tactics and knowledge, and presenting only what is specifically tailored and useful to civilian community-defense use.  No more needing to wade through hundreds of pages of military Field Manuals (FMs), while glossing over topics largely not applicable to civilians, to get to the good stuff.  Max also mixes in a hearty supply of Standard Operating Procedure (SOP) and distilled experience.

Handbook to Practical Disaster Preparedness for the Family, 3rd Edition

This book contains a wealth of very down-to-earth knowledge about planning and preparing for disaster survival.  It takes a very intelligent approach, and includes lots of planning aids, that is a refreshing departure from the typical "store 10 years of food in your basement" books.  It's a comprehensive and sensible place to start for many new and experienced preppers alike.

Patriot Dawn: The Resistance Rises

This novel is very detailed in its use of proper military techniques, and will give people with no military background the story context needed to better-understand how those tactics are employed.  This contextual understanding is often one of the hardest barriers for civilians to overcome.  It's a great compliment to Max Velocity's other book, "Contact! A Tactical Manual for Post Collapse Survival".

TM 3-34.85 (FM 5-34)/MCRP 3-17A, Engineer Field Data, October 2013

This Army Training Manual (TM) contains a countless charts, calculations, illustrations, and descriptions for construction and employment of fighting emplacements, field fortifications, anti-vehicle / counter-mobility obstacles, etc.  Like most Army publications, probably 70% of the guide is too specific to be useful in a civilian setting (e.g. load-bearing characteristics of military Bailey Bridge devices), but that shouldn't keep you from owning a copy.

STP 31-18-SM-TG , Soldiers Manual and Trainiers Guide, CMF 18, SF Common Skills, SL 3 and 4

This is the guide of "common skills" trained to all Army Special Forces personnel, regardless of specialization.  It contains illustrated instruction, as well as task checklists to identify training objectives and evaluate soldiers.  Use this book to take advantage of the extensive work the Army has done to identify the mission essential tasks of guerrilla leaders.

The Last Hundred Yards - The NCO's Contribution to Warfare

This book details many Small Unit Tactics (SUT) ideas that are not found in almost any other source.  While some portions show the book's 25+ year age, much of the content is timeless for the light infantryman.  NOTE: This book is restricted for sale to active-duty, reserve, college ROTC, retired or veteran U.S. military personnel only, though it can be found used on Amazon without restriction.

Light Infantry Tactics: For Small Teams

This book is essentially a layman-friendly rewrite of Army FM7-8, Infantry Platoon and Squad.  It includes nice pictures and illustrations, as well as lots of advice and tips not present in the original manuals.  It's very well written and easy to understand.

Combat Leader's Field Guide: 13th Edition

While not a book on tactics, this guide includes many checklists and concise explanations that are useful to the small unit leader.