The Original Rules
The rules tell us something about the challenges faced by the early golfers and the society they lived in. They are reproduced below, followed by what appears to be the first amendment, after "frequent dispute". 

They seem minimal when compared with all the rules, sub-sections and special rulings - many created after "frequent dispute" ! - that comprise the modern-day rule book. 

However, the essence and spirit of the game that they capture bears a striking similarity to our modern rules.

Our current Secretary, Brian Graham, received a gift of a framed copy of the rules, number 223 of a limited edition of 1,000, produced by the Honourable Company of Edinburgh Golfers. [more]

Articles & Laws in Playing at Golf - 7th March 1744

1. You must Tee your Ball within a Club's length of the Hole.
2. Your Tee must be upon the Ground.
3. You are not to change the Ball which you Strike off the Tee.
4. You are not to remove, Stones, Bones or any Break Club, for the sake of playing your Ball, Except upon the fair Green & that only within a Club's length of your Ball.
5. If your Ball comes among Watter or any wattery filth, you are at liberty to take out your Ball & bringing it behind the hazard and Teeing it you may play it with any Club and allow your Adversary a Stroke for so getting out your Ball.
6. If your Balls be found any where touching one another, You are to lift the first Ball, till you play the last.
7. At Holling, you are to play your Ball honestly for the Hole, and, not to play upon your Adversary's Ball not lying in your way to the Hole.
8. If you should lose your Ball, by it's being taken up, or any other way, you are to go back to the Spot where you struck last, & drop another Ball, And allow your adversary a Stroke for the misfortune.
9. No man at Holling his Ball, is to be allowed, to mark his way to the Hole with his Club, or anything else.
10. If a Ball be stopp'd by any person, Horse, Dog, or any thing else, The Ball so stop'd must be play'd, where it lyes.
11. If you draw your Club in order to Strike & proceed so far in the Stroke as to be bringing down your Club; If then, your Club shall, break, in any way, it is to be Accounted a Stroke.
12. He, whose Ball lyes farthest from the Hole is obliged to play first.
13. Neither Trench, Ditch or Dyke, made for the Preservation of the Links, nor the Scholar's Holes or the Soldier's Lines, shall be accounted a Hazard; But the Ball is to be taken out / Teed / and play'd with any Iron Club.

John Rattray, Captain

[Rule 13 appears to be a local rule, but the others are relevant to the general principles of how the game was played at that time].

Amendment to the Articles & Laws - 1758

The 5th and 13th Articles of the foregoing Laws having occasioned frequent Disputes it is found convenient that in all time coming, the law shall be, that in no case whatever a ball shall be lifted without losing a stroke except it is in the Scholars holes when it may be taken out, teed and played with any Iron Club without losing a Stroke - And in all other cases the ball must be played where it lyes, except it is at least half covered with Water or filth when it may, if the player chuses, be taken out, teed and played with any club upon loosing a stroke.

Thomas Boswall, Captain