The Ranger Handbook has some basic but important things in it. You should probably have a small copy with you when you can.
It is not going to keep you entertained for hours. The illustrations are not very good either, but it is the go-to for basic things you as a Soldier should know.
Use this and The SUT Handbook as references.
The Official US Army Ranger Handbook, as used in Fort Benning as of February 2011.
RANGER CREED :
Recognizing that I volunteered as a Ranger, fully knowing the hazards of my chosen profession, I will always endeavor to uphold the prestige, honor, and high esprit de corps of the Rangers.
Acknowledging the fact that a Ranger is a more elite Soldier who arrives at the cutting edge of battle by land, sea, or air, I accept the fact that as a Ranger my country expects me to move further, faster, and fight harder than any other soldier.
Never shall I fail my comrades I will always keep myself mentally alert, physically strong, and morally straight and I will shoulder more than my share of the task whatever it may be, one hundred percent and then some.
Gallantly will I show the world that I am a specially selected and well-trained Soldier. My courtesy to superior officers, neatness of dress, and care of equipment shall set the example for others to follow.
Energetically will I meet the enemies of my country. I shall defeat them on the field of battle for I am better trained and will fight with all my might. Surrender is not a Ranger word. I will never leave a fallen comrade to fall into the hands of the enemy and under no circumstances will I ever embarrass my country.
Readily will I display the intestinal fortitude required to fight on to the Ranger objective and complete the mission, though I be the lone survivor