The JBoss application server development had been moved to WildFly (WildFly Homepage · WildFly)
If you are new to WildFly you might want to start with the WildFly documentation (https://docs.jboss.org/author/display/WFLY9/Documentation)
But the Java EE tutorial (Java Platform, Enterprise Edition: The Java EE Tutorial Release 7 - Contents) might also provide a good background knowledge.
Of course there are also some Wildfly/JEE books on the market (eg Amazon.com: WildFly 8 Administration eBook: Francesco Marchioni, Jaikiran Pai, Mylos Kathos, Brian Stansberry: Kindle St…).
But the problem with such printed books is very often that they do not describe the latest versions.