And what is the Quest?

He wrote a series of dark fantasy novels, which come under the series name: The Dark Tower.
 
 

The plot summary of all that is going on (i.e. plot spoiler) can be found at: 
 
 

http://www.geocities.com/jordanlund/dtfaq1.htm 
 
 

Basically, it's a tale of a man, a Gunslinger, called Roland who is trying to save his world....his universe, Mid-world, from destruction. The only way he knows of how to do it is to reach a place that appears to be the linchepin of all of creation (for all realities) and set things to right. How, exactly, remains to be seen. 
 
 

What is certain, however, with recent events back on Terra Prime and elsewhere, one has to wonder what Roland will actually find when he gets there with his fellow adventurers. 
 
 

See, that is the Quest of Queen Astra and the others: to get him to the Dark Tower alive and whole! That, and get him there quickly! 
 
 

That is what Astra tells Queen Rua'othi Lishe , leader of the Light Elves. 
 
 

She had been attending the play when these strangers had apeared from nowhere. She had Felt their presence even before they had arrived, and knew that Those she served wished them to be away....and as quickly as possible....on this quest. 
 
 

As a servant of the Goddess, she would be more than foolish to disobey! 
 
 

"So be it," the regal figure (which stood as tall as Astra) says. 
 
 

She raises her scepter, and sends most of the adventurers on their way ahead of her two newest subjects. 
 
 

"It would not do for you to go in mere costumes," she says softly. 
 
 

Ia'adoire and Lueoth suddenly are dressed in sturdy adventurer garb, complete with weaponry. 
 
 

"But....how shall we return to here?" Lueoth protest, seeing what is coming next. 
 
 

"You shall not," the Elfin Queen says firmly, "We have been ordered by the Goddess that thee shall depart, never to return. Go with your new Court, and forevermore be a part of them.....Astra and Frederigo.....now Lueoth and Ia'adoire. Go with Our love, and wishes for the best." 

And thus she is then alone. 

The Champions arrive rather uncerimoniously on the bullet train that Roland and company have gotten onto in order to traverse the poisoned lands relatively safely 
between the now defunct town of Lud and Topeka. 

The insane computer known as Blaine was asking for Roland to ask him some riddles right before he causes the train to derail at high speeds in Topeka when the unusual guests arrived....out of thin air. 

Everyone pauses in surprise.  But who is everyone in Roland's group?