1. Out Hit the ball twice
(a) The striker is out Hit the ball twice if, while the ball is in play, it strikes any part of his person or is struck by his bat and, before the ball has been touched by a fielder, he wilfully strikes it again with his bat or person, other than a hand not holding the bat, except for the sole purpose of guarding his wicket. See 3 below and Laws 33 (Handled the ball) and 37 (Obstructing the field).
(b) For the purpose of this Law, 'struck' or 'strike' shall include contact with the person of the striker.

2. Not out Hit the ball twice
Notwithstanding 1(a) above, the striker will not be out under this Law if
(i) he makes a second or subsequent stroke in order to return the ball to any member of the fielding side. Note, however, the provisions of Law 37.4 (Returning the ball to a member of the fielding side).
(ii) he wilfully strikes the ball after it has touched a fielder. Note, however, the provisions of Law 37.1 (Out Obstructing the field).

3. Ball lawfully struck more than once
Solely in order to guard his wicket and before the ball has been touched by a fielder, the striker may lawfully strike the ball more than once with his bat or with any part of his person other than a hand not holding the bat. Notwithstanding this provision, the striker may not prevent the ball from being caught by making more than one stroke in defence of his wicket. See Law 37.3 (Obstructing a ball from being caught).

4. Runs permitted from ball lawfully struck more than once
When the ball is lawfully struck more than once, as permitted in 3 above, only the first strike is to be considered in determining whether runs are to be allowed and how they are to be scored.
(a) If on the first strike the umpire is satisfied that
either (i) the ball first struck the bat
or (ii) the striker attempted to play the ball with his bat
or (iii) the striker tried to avoid being hit by the ball then any penalties to the batting side that are applicable shall be allowed.
(b) If the conditions in (a) above are met then, if they result from overthrows, and only if they result from overthrows, runs completed by the batsmen or a boundary will be allowed in addition to any penalties that are applicable.
They shall be credited to the striker if the first strike was with the bat. If the first strike was on the person of the striker they shall be scored as Leg byes or No ball extras, as appropriate. See Law 26.2 (Leg byes).
(c) If the conditions of (a) above are met and there is no overthrow until after the batsmen have started to run, but before one run is completed,
(i) only subsequent completed runs or a boundary shall be allowed. The first run shall count as a completed run for this purpose only if the batsmen have not crossed at the instant of the throw.
(ii) if in these circumstances the ball goes to the boundary from the throw then, notwithstanding the provisions of Law 19.6 (Overthrow or wilful act of fielder), only the boundary allowance shall be scored.
(iii) if the ball goes to the boundary as the result of a further overthrow, then runs completed by the batsmen after the first throw and before this final throw shall be added to the boundary allowance. The run in progress at the first throw will count only if they have not crossed at that moment; the run in progress at the final throw shall count only if they have crossed at that moment. Law 18.12 (Batsman returning to wicket he has left) shall apply as from the moment of the final throw.
(d) If, in the opinion of the umpire, none of the conditions in (a) above have been met then, whether there is an overthrow or not, the batting side shall not be credited with any runs from that delivery apart from the penalty for a No ball if applicable. Moreover, no other penalties shall be awarded to the batting side when the ball is dead. See Law 42.17 (Penalty runs).

5. Ball lawfully struck more than once - action by the umpire
If no runs are to be allowed, either in the circumstances of 4(d) above, or because there has been no overthrow and
(a) if no run is attempted but the ball reaches the boundary, the umpire shall call and signal Dead ball and disallow the boundary.
(b) if the batsmen run and
(i) neither batsman is dismissed and the ball does not become dead for any other reason, the umpire shall call and signal Dead ball as soon as one run is completed or the ball reaches the boundary. The batsmen shall return to their original ends. The run or boundary shall be disallowed.
(ii) a batsman is dismissed, or if for any other reason the ball becomes dead before one run is completed or the ball reaches the boundary, all the provisions of the Laws will apply except that the award of penalties to the batting side shall be as laid down in 4(a) or 4(d) above as appropriate.