A spell to summon a dead person
This should be carefully distinguished from A spell to restore the dead to life. In the latter, the attempt is made to restore the spirit to the body: but in the case of summoning a dead person, there is no attempt to reunite body with soul. Rather, the magician seeks only to communicate with the spirit of the dead, in order to learn something of use.
Early in his career Jonathan Strange used such a spell to invoke the presence of Maria Absalom, with a view to asking her to instruct him in magic; and he later causes an uproar by writing an article in The Famulus recommending to all and sundry this method of learning. (Though his article caused a sensation with the public, and gave the deepest alarm to Gilbert Norrell, Strange's recommendation was not novel: the eminent Dr. Pale, by his own account, learnt magic by this means, gaining the invaluable help of Catherine of Winchester) .