Codex Space Wolves (HB) (9th Edition) contains:

The History Of The Space Wolves, With A Look At How They Relentlessly Take The Fight To The Enemies Of The Allfather Across The Sea Of Stars
A Space Wolves Bestiary With Background Details For Every Unit And Character Featured
A Showcase Of Stunningly Painted Citadel Miniatures
Rules For Space Marines Units That Are Uniquely Available To The Space Wolves
Rules For Sagas – A Unique Form Of Warlord Traits – And How The Mighty Heroes Of The Chapter Can Inspire Their Battle-Brothers By Performing The Deeds Associated With Them
Stratagems, The Bespoke Tempestas Psychic Discipline, Relics Of The Fang, And Optional Secondary Objectives That Define The Ways That The Space Wolves Wage War
Bespoke Crusade Rules Providing New Agendas, Requisitions, Battle Traits, Honorifics, And Crusade Relics That Are Unique To The Space Wolves
And More!

You will need a copy of Codex: Space Marines and the Warhammer 40,000 Core Book to use the rules included in this codex.