Robert's Rules of Order was first published in 1876 by U.S. Army officer Henry Martyn Robert,
who adapted the rules and practice of Congress to the needs of non-legislative societies.
He later produced two revised editions, and his heirs have produced additional revisions.
The current edition of Robert's Rules of Order Newly Revised (RONR) was published in 2011.
The original works by General Robert are in the public domain, and are still in use. Other authors
have produced versions which may be shorter and easier to master, but RONR is
considered the most authoritative. When using Robert's Rules in a meeting, it's important to specify
which version the group relies on, since there are some differences in the rules,
mostly on finer points.
Original 1876 Edition - Project Gutenberg (free)
Robert's Rules of Order Revised (ROR), by Henry M. Robert (free, 1915 version, still in use)
Robert's Rules of Order Revised (ROR), by Henry M. Robert (free PDF)
Robert's Rules of Order, The Modern Edition, revised (1996)
Simplified and updated by Darwin Patnode, PhD, past President of the American Institute of Parliamentarians. Update of the original 1876 edition.
Robert's Rules in Plain English, Second Edition (2009)
by Doris P. Zimmerman. "A readable, authoritative, easy-to-use guide to running meetings."
Robert's Rules of Order Newly Revised, 11th Edition (RONR)
Multiple authors. 669 pages of text, plus tables and index. Comprehensive and authoritative.
Robert's Rules of Order Newly Revised in Brief, 2nd Edition (2011)
Companion book to RONR. Readable, true to the authoritative RONR, but not itself authoritative. In the words of the authors, "For one who will brave it, RONR is written to serve as a self-explanatory text
that can be read through, with topics presented in an order that will best convey an overall understanding of the entire
subject matter. You need not apologize, however, if you find that to be a bigger project than you would like to take on at this point.
If you are such a person, and want to know how to get by in a meeting or as a club president, this brief book is for you."
Many more titles available online.