Oracle8i Internal Services for Waits, Latches, Locks, and Memory
Out of number of great "Oracle internals" book this definitely stands out. Ignore 8i - wealth of information in this book deserves it to be read and reread.
I met author in 2001-2002 and he is a shy and very smart DBA from Australia. His website http://www.ixora.com.au/ is a treasure of Oracle internals information and should be studied and used by every reasonable good Oracle DBA.
This Book explain in a great depth internal work of different latches and locks - knowledge which DBA must have to resolve and identify root causes of very complex contentions.