From wikipedia (http://en.wikipedia.org/wiki/Warhammer_Fantasy_Battle):
In 1984 the second edition was released, incorporating some of the Forces of Fantasy material, White Dwarf articles and Citadel Compendium material. Again a boxed-set of three black and white books (with colour covers). Combat explains the core rules and turn sequence, Battle Magic which largely retains the system as the 1st Edition, as well as adding specialities of Illusionists, Demonologists, Elementalists, and removing the requirements for Amulets. The centre pages are an introductory scenario "The Magnificent Sven" for which cardstock figures were also supplied in the box. The Battle Bestiary book features descriptions of the races, monsters and includes several example Army Lists and a Points System for players to develop their own open-ended armies.
Also in the Battle Bestiary is the first appearance of the Warhammer 'Known World' along with a map, and a timeline which includes the Slann, Incursions of Chaos, inter-elf wars and The Empire. Minor rules modification included rationalising all statistics to use numbers, and increasing all creatures' Strength by +1.