Teeing Ground
Order of play
Falling off tee

Playing the Ball
Unplayable
Wrong, Substitute
Lifting, dropping
Moved, deflected

Provisional, Lost, Out of bounds

Putting Green
Flagstick
Marking, lifting
Stymie

Hazards
Water hazards
Lateral water hazards

Abnormal Conditions
GUR
Casual water, Temporary water
Hole, cast, or runway

Obstructions,
Loose impediments

Clubs
There were no rules governing clubs until 1908, or balls until 1921. 

The statement at the end of the 1908 rules introduced the first regulations on form and make of clubs.  A club comprised 'a plain shaft and a head which does not contain any mechanical contrivance, such as springs'.

In 1909 the Committee issued two decisions which led to a difference of opinion between the R&A and the USGA which lasted until 1952.  The 1910 amendment had the additional statement about centre-shafted putter, "....it also regards as illegal the use of such clubs as those of the mallet-head type, or such clubs as have the neck so bent as to produce a similar effect."

1909 decisions

229: Nga Motu Golf Club, New Zealand.
With regard to 'Make and Form of Golf Clubs' is it permissible to use a small croquet mallet to putt with?
Answer: A croquet mallet is not a golf club and is inadmissible.

230: Pickeridge Golf Club
In a stroke competition a competitor used a putter made in the form of a croquet mallet. Is he disqualified?
Answer: The Rules of Golf Committee is of opinion that the time has come for the Royal and Ancient Golf Club to decide at a General Meeting whether the various mallet-headed implements at present in use are to be permitted or not.
The Rules of Golf Committee is, however, of opinion that it is not allowable to employ the vertical croquet stroke as a method of putting.

The Committee considers that it is much to be deplored that players, instead of trying to master the use of golf clubs, should endeavour to overcome the difficulties of the game by using implements which have never been associated with it.

Example of the Schenectady putter Photo courtesy of Graham Rowley

Note that in this decision, the Committee were of the opinion that a vertical croquet-style putting stroke was not allowable.  It wasn't until 1968 that the standing astride the line style of putting (i.e. a croquet stroke) was actually made illegal.

As far as the R&A was concerned these decisions effectively banned the Schenectady putter, which was in widespread use in the USA.

The USGA adopted the revised rules without change, but chose to interpret the rule differently, keeping the Schenectady putter legal in the USA.  They considered a mallet putter was one with a right-angled, centred shaft and two striking faces; the R&A interpretation was that any putter where the shaft inserted anywhere in the head except at the heel, or had the neck bent to achieve the same effect, was illegal.

Wry-neck, centre-shafted, and mallet-headed clubs in the British Golf Museum

July 1921 deeply grooved irons made illegal by the R&A.

Jan 1924 ‘Corrugated, grooved or slotted’ clubs banned by USGA, but scored or punched club faces ‘in a manner customary for a number of years’ remain legal.

1931 Clubs with concave faces banned.

1947 USGA. Grips must be substantially straight and plain, but may have flat sides. From 1949, grip may not have a channel or furrow, or be moulded for the fingers. Incorporated into the joint rules, 1952.

Clubs with movable or adjustable parts banned, adjusted to say 'except for weight' in 1972, then an exception for putters from 1988.

1952 Putter shafts may be fixed at any point in the head.

1956 Playing characteristics of a club may not be changes during a round.
Clubs with more than one striking face banned, except putters. The loft on a putter's face must be 'practically the same'.
From 1976, the loft must not exceed 10 degrees.

1984 Club grips must be circular in cross section, except for putters. Putters may have more than one grip 1992.

1988 Minimum length of 18 inches (457mm) for shafts stipulated.

2004 Maximum length for club shafts introduced, being 48 inches (1219mm) for all clubs except putters, with a grace period for current clubs which exceed the specifications until 31 Dec, 2004.
Also included is a limit to the clubhead size. A clubhead's maximum volume is 460cc, with a tolerance of 10cc., coupled with a maximum heel to toe length of 5 inches (127mm) and a maximum height (sole to crown) of 2.8 inches (71.1mm).

Steel shafts were initially banned by the R&A and USGA in 1914 as "not a permissible departure from the traditional form and make of golf clubs". However, following further developments and pressure from manufacturers, the increasingly popular steel shafts were legalised in April 1924 by the USGA, and in Sept 1929 by the R&A, the main reasons being that steel shafts conferred no playing advantages, and conservation of the world's supply of hickory.

The flexibility of approach to shot making from hickories was stifled by steel-shafted clubs, so players chose to carry a large number of them of them in order to re-create the strokes required on the course.  This prompted the USGA into limiting the number of clubs carried to 14 on 1 Jan 1938; the R&A followed suit 1 May, 1939.
The penalty for carrying excess clubs was initially disqualification, then in 1956 changed to a slightly more lenient two strokes per hole/loss of each hole for a violation. Nevertheless, a possible 36-stroke penalty or loss of 18 holes is still pretty harsh.
1964 the penalty was capped and became a maximum of loss of two holes in match play or 4 strokes in stroke play per excess club.
The current limit of loss of two holes or 4 strokes was introduced in 1968.

Following on from these changes, the issue of replacing damaged clubs arose.  The USGA in 1938 and the R&A in 1950 allowed replacement or borrowing (but not from another player), refined in 1952 to a club damaged 'in the normal course of play'.

1988 rules allowed borrowing from anyone, but only the borrower could then use the club for the rest of the round. The pre-1988 wording was restored in 1992.

The 'mechanical contrivance' restriction introduced in 1908, or a spring-like effect as it was termed from 1984 came back into prominence with the manufacture of clubs whose faces had a high coefficient of restitution (COR).
In August 2002, the USGA placed an upper limit of 0.83 for clubs with a loft of 15 degrees or less. The R&A decided not to put a COR limit in place, but did enable Committees to put a limit of 0.83 as a Condition of Competition from 1 Jan 2003 until Dec 31, 2007.
From 2004, the ruling bodies have chosen a simpler method of calculating the spring-like effect of clubs by using the 'characteristic time', that is the time that a ball remains in contact wth the club face during a stroke. The limit is 239 µs, plus a tolerance of 18µs.

"Driving clubs must not have a characteristic time greater than 257 microseconds when measured on pendulum testing apparatus approved by R&A Rules Limited."

Balls
Way before any known rules, golf balls were made from wood, but the featherie is perhaps the best known early ball.  The featherie was used from the 1600s until the better, cheaper, gutta-percha ball, introduced in 1848, quickly superseded it.  None of these balls came under the scrutiny of the Rules. The size and weight of such balls, especially the featheries, was up to the owner's taste; some players drilled holes in their balls and filled them with lead shot at times when a heavier ball was advantageous, such as in high winds.

The gutta-percha, commonly known as a guttie, made a big difference to the popularity of golf not just because of its better performance but the lower cost allowed many more people to take up the game (a featherie could be more expensive than a club).
Increasing industrialisation at the same time led to balls being mass produced.  The better and more consistent characteristics of the guttie improved scoring - R&A records show that the average score of the Open Champion fell by 3 strokes with the introduction of the guttie balls.  One drawback of these balls was that they had a tendency to break, leading to a rule covering the eventuality.  The R&A allowed a ball to be substituted but in rather uncertain terms, in the 1850s.  In 1875 a player could put down a new ball where the largest piece lay, amended slightly in 1891 to being where either piece lay if they were of approximately equal size, and finally to wherever any piece lay in 1908.

The rubber-cored, Haskell ball was introduced in 1898.  Again, there were advantages in performance and durability over the guttie and this wound type ball with a rubber outer covering dominated (balata was first used in 1904). The wound rubber ball was first used in the 1902 Open by only a few players, including the eventual winner Alex Herd; in 1903 almost every player was using it. The Open Champions’ scoring average in the ten years prior to 1902 was 78.5, for the period 1902-1926 it fell to 75.1, and to 74.5 for 1902-1933.

The better durability was perhaps the reason that in 1933, rule 24 did not mention a ball breaking into pieces separately, but was reworded as being 'so damaged as to be unfit for play'.  The rule reappeared in 1976, specifying the player was to replay the stroke.

Coincidentally, another invention made its debut within a year or two of the Haskell ball: the golf tee (see Teeing ground).

The featherie balls varied quite a bit in size and weight; weights ranged between 26 dwt (the 'floater'), and 31dwt. Standardisation came with the more repeatable manufacturing methods first used in moulding gutta percha. The gutties also floated.
You may not be au fait with pennyweights, so here's the translation: 26 dwt is 1.43oz (40.5g) and today's ball weighs 29.5 dwt.

The 1920 Rules were the first to specify ball characteristics of 1.62oz and 1.62".
The USGA favoured a slightly bigger ball; there was an experimental 1.7" ball without weight restriction introduced in 1922. However, in 1930 USGA adopted a 1.68", 1.55oz ball for the year 1931 but the universal condemnation of this balloon made them quickly re-think, and from January 1932 settled on the 1.68", 1.62oz specifications.
The R&A considered allowing the 1.68" ball as long ago as 1936, but decided on no change, nor again in 1947 after procrastination from R&A affiliates.

R&A and USGA experimented with a 1.66" ball and considered its introduction in 1973, but the fear of antitrust law suits left them with no option but to go for the 1.68" ball.

In the USA, International teams were allowed to use the small ball.
The PGA made the bigger ball compulsory for main tournaments in 1964, and from 1968 announced that it was to experiment with the bigger ball of 1.68" in its tournaments, and soon after made it mandatory.
In 1974, the R&A made the bigger ball compulsory for the Open Championship.
Under the R&A, both balls were legal until the smaller ball was finally outlawed by the R&A in 1990.

The idea of limitations on the distance achieved by balls was first discussed between 1912 and 1920.

1942 The USGA imposed a limit on the velocity a golf ball may have at impact - 250 feet per second (with a tolerance of 2%) when measured under controlled conditions on the Association's testing device.
The R&A introduced a similar velocity test in 1976.

In 1984 an Overall Distance Standard of 280 yards (±6%) was introduced. It was increased to 320 yards in June 2004. There is no change in the characteristics of balls; the change comes about due to the modernisation of the test equipment used.

The use of a ball with a small transmitter inside, to allow a player to use a radio receiver to locate his ball, was invented in 1973 and the use of such a receiver was promptly banned from competition use by both authorities.