1. For the space of one entire month (from full moon to full moon), a single leaf from a Mandrake must be carried constantly in the mouth. The leaf must not be swallowed or taken out of the mouth at any point. If the leaf is removed from the mouth, the process must be started again.    

2. Remove the leaf at the full moon and place it, steeped in your saliva, in a small crystal phial that receives the pure rays of the moon (if the night is cloudy, you will have to find a new Mandrake leaf and begin the whole process again). To the moon-struck crystal phial, add one of your own hairs, a silver teaspoon of dew collected from a place that neither sunlight nor human feet have touched for a full seven days, and the chrysalis of a Death’s-head Hawk Moth. Put this mixture in a quiet, dark place and do not look at it or otherwise disturb it until the next electrical storm.

3. While waiting for the storm, the following procedure should be followed at sunrise and sundown. The tip of the wand should be placed over the heart and the following incantation spoken: ‘Amato Animo Animato Animagus.’

4. The wait for a storm may take weeks, months or even years. During this time, the crystal phial should remain completely undisturbed and untouched by sunlight. Contamination by sunlight gives rise to the worst mutations. Resist the temptation to look at your potion until lightning occurs. If you continue to repeat your incantation at sunrise and sunset there will come a time when, with the touch of the wand-tip to the chest, a second heartbeat may be sensed, sometimes more powerful than the first, sometimes less so. Nothing should be changed. The incantation should be uttered without fail at the correct times, never omitting a single occasion.

5. Immediately upon the appearance of lightning in the sky, proceed directly to the place where your crystal phial is hidden. If you have followed all the preceding steps correctly, you will discover a mouthful of blood-red potion inside it.  

6. It is essential to move, at once, to a large, secure place where your transformation cannot cause alarm or place you in physical danger. Place your wand-tip against your heart, speak the incantation ‘Amato Animo Animato Animagus,’ and then drink the potion.

7. If all has gone correctly, you will feel a fiery pain and an intense double heartbeat. Into your mind will come the shape of the creature into which you are shortly to transform. You must show no fear. It is too late, now, to escape the change you have willed.

8. The first transformation is usually uncomfortable and frightening. Clothing and items such as glasses or jewellery meld to the skin and become one with fur, scales or spikes. Do not resist and do not panic or the animal mind may gain the ascendancy and you could do something foolish, such as try to escape through a window or charge a wall.

9. When your transformation is complete you should find yourself physically comfortable. You are strongly advised to pick up your wand at once, and hide it in a place of safekeeping, where you will be able to find it when you regain a human form.

10. To return to a human form, visualise your human self as clearly as you can. This should be sufficient, but do not panic if the transformation does not occur immediately. With practice, you will be able to slip in and out of your animal form at will, simply by visualising the creature. Advanced Animagi can transform without wands.