But what about the bible? Okay, Okay!! Of course you need the bible first and foremost above all else. You happy now!! But then, honestly, I don’t consider the bible to be just a “book”. Yeah, so who’s the spiritual one now – loser.
Seriously though, when it comes to engaging in real bible study there are really only two books you will need. Here they are:

Strong’s Exhaustive Concordance
The new expanded version is filled with useful resources. Strong’s is essential for a successful word study. The dictionary in the back will provide you with a very brief definition of the word and the concordance will help you find all the places that word is located in the bible for comparing scripture with scripture. These two used together will help you form a fuller definition. Remember a word is not defined by etymology, it is defined by usage. Strong’s will enable you to see how the word is used throughout the bible.
The Treasury of Scripture Knowledge
This resource is gold. If you don’t have one then you are not saved. Okay, not really, but it is an awesome tool. In The Treasury of Scripture Knowledge, you can go to any passage in the bible and it will provide you with a wealth of cross references. This will provide additional light on the passage you are studying and enable you to stack precept upon precept, line upon line (Isaiah 28:9-10) so that you might fully understand and explain the doctrine being taught in the passage.
These two books are the pick axe and shovel you need to dig into any passage of the bible and find the treasures of wisdom that are hidden there. There are other resources available, but through prayer and the guidance of the Holy Spirit, these two books are really all you need to enjoy genuine, “blow your hair back” bible study.
Now, go grab a copy of each. You can also find bible programs that provide both of these. Then pick a passage to study, and just follow where the evidence leads you. You will be amazed at what you discover.