The Complete Aliens Omnibus

Original Sin
>Centuries after the death of the original Ellen Ripley, her clone has joined the fight against the Alien threat. With the help of an android named Call, a brutal hired gun named Johner, and a paraplegic mechanic named Vriess, she will battle an Alien horror, and discover the answer to a question that pierces the Alien mystery to its seething acid-chamber of a heart.

DNA War
by Diane Carey
In a bleak galaxy, the hospitable planet Rosamond 6 is a rare find. But while it may look like an oasis among the stars, it harbors a fatal secret: it is infested with Aliens. Eager to prove her theory that the Aliens can be reasoned with, anthropologist Jocasta Malvaux has set up an observation post there. And something unexpected happens: the Aliens don't attack. But, why? Could it be that the monsters are evolving? Or is it a matter of time until every person on the planet must fight for their lives?