I’ve been asked the same question by multiple people, around what books by what authors are good to have, so let me answer it once here. 🙂
The answer is easy – it depends! Are you interested in database administration? Application development against an Oracle database? Technical apps? Functional apps? High Availability? Enterprise Manager? No single author covers all of those – unless you count the Oracle documentation set as a single author.
To make life more difficult, it also depends on what your current level of knowledge and understanding is. If you’re a beginner, it may be better to go to courses delivered by a reputable organization than to try and pick things up from a book, particularly if you also want hands on experience. If you’re more experienced, courses may not be the path for you – but books may also not be the right path. Using online discussion forums like the oracle-l list, interacting with peers via user groups, attending conferences (like RMOUG Training Days, the Hotsos Symposium, UKOUG Tech Days, the DOAG conference, ODTUG’s KScope etc.) may be better.
Yes there are some authors I will always recommend – anything written by Jonathan Lewis and Tom Kyte always works for me. But that only covers a small portion of the whole gamut of material that’s available out there, and it’s what works for me. It may not be suitable for you.
So the answer is there is no easy answer – get out there and try it all and see what works best for you!