Nowadays there is no much time to read Oracle books (I mean the real books). We rather to search in Metalink, Google or other Oracle related sites. As we all know, those books are not cheap. If we do want to buy them, we would like the company to pay for the bills:-)
Actually, we can find lots of Oracle books for online reading. Here is an example. You can search Oracle book by using Google Book:
You can even fine-tune your search. Here are some books for your reference:
Oracle Essentials: Oracle Database 10g
Oracle Performance Tuning
Oracle High Performance Tuning for 9i and 10g
Oracle Performance Troubleshooting: With Dictionary Internals SQL & Tuning
Be aware: you can NOT read full pages of the above books. If you feel those books really good, you will have to buy by yourself or company. Anyway, enjoy!