The last book of WLS 12.1.1, Packt brings us a 285 pages product, a comfortable size, not very big neither a flyer, so, easy to read and search as a reference, kind of cookbook with high availability and clustering point of view.
First pages are very detailed in how to install and run a vanilla WLS domain (including Node Manager, Machines, etc.). Including WLST and Admin Console. Some aesthetic tips, but not sure if this ha Administrator flavor.
Later comes deployments in different approaches (tools actually:) ). Next Chapter about High Availability and Clustering fine grained; address listen, Broadcasting, Unicast, Multicast, etc.
Then JDBC, again with HA/Clustering thru WLST/Admin Console... here it is more verbose about algorithms, Parameters of Data Sources, Gridlink, Multidatasource, a must for any Admin.
JMS, focused to HA again, using all typical resources of it: Bridges, Persistent Stores, etc.
A good, perhaps more useful , about monitoring, tips & tricks on this which is not very documented, and this time is very admin focused. Then recipes for WLS 12.1.1 troubleshooting for OutOfMemory (a very common scenario).
Finishing with security & SSL, concurrent questions and answer on this topic (X.509 certificates, keystore, etc.)
I can say that has some known areas, but improves in another that many times are left for the user, and it doesn't appear in the official documentation. 
