From "The Evolution of Arms Law (1980-2003)" by Brent Knorr:
The first version of Arms Law produced by ICE was printed in 1980. This underwent three printings, the first with a blue and white cover, then two with a black and white cover. There was also a fourth printing that combined Arms Law and Claw Law and had a color cover. The books themselves have First, Second, Third, and Fourth Edition printed on them, but this really refers to which printing the book is, all of these are considered to be First Edition Rolemaster products.
The first printing has a 24-page booklet with 30 Attack Tables on heavy grey blue card stock paper. The sheets with the Attack Tables are single sided. The Maneuver Chart and Critical Tables are printed on heavy yellow card stock, double sided.
The second printing contains a small booklet of twelve pages. It has the same material as the booklet for the first printing, but uses a much smaller font. The Attack Tables are printed on the same stock as the first printing, but double sided. The Maneuver Chart and Critical sheets are the same as the first printing. These originally came in a bag and later in a box. The third printing is a saddle-stitched book with perforated pages also on heavy card stock.
Arms Law contains several sections, an Introduction, Definitions, a Tactical Combat Sequence section, which describes the Battle round sequence which is broken down into nine phases.
The fourth section covers Defensive Capabilities in Combat, including descriptions of armor, shields, defensive bonus, and parrying options. Section five covers Offensive Capabilities in Combat including weapon/weapon combinations, and offensive bonuses.
Section six is resolution of combat, including first swing determination and swing and missile attack resolution. The section explains how to use the attack charts and the critical tables.
Section seven covers maneuvering, orientation, and movement.
The tables are section eight. There are five critical strike tables including a slash table, puncture table, crush table, large creature table and super large creature table. It also includes tables for 30 different weapons. There is also a maneuver table and a fumble table. The color text on the critical tables is handwritten.
The second printing of Arms Law includes an additional section nine, which adds sections on mounted combat, pole arms options, thrown weapons and missiles in melee, two weapon combinations, bow preparation time, notes on changes to some of the tables since first printing, notes announcing the release of Claw Law, and conversion notes explaining how to use Arms Law with Advanced Dungeons and Dragons.
The third printing has some modifications in organization and format and has some additional sections on healing, slaying weapons and armor bonuses.