Summoning is a members-only skill which was released on 15 January 2008 and expanded on 31 March 2008. Wolf Whistle acts as an introduction to the skill, even though it is not required to start the skill. It teaches players to infuse the essence of a variety of creatures into Summoning pouches, then summon these creatures, called familiars.
Each familiar has a unique ability that requires a Summoning scroll, made from a corresponding pouch. Summoning familiars and creating scrolls offer very little experience, so players must create pouches in order to gain experience effectively, and it is a slow skill to train.
Although Summoning is a slow skill to train, it is one of the most useful skills which can not only help you last longer at bosses, but also be helpful in training certain skills like Hunter or Runecrafting.