A guitar is made for creating all kinds of music be it classic rock, flamenco, country music. It's a wonder that same instrument can be used to produce such a wonderful array of music.

Acoustic Guitar: An acoustic guitar is one that is made of dried wood. This is most important thing to note, that wood needs to be dried either naturally or using artificial methods. In all old times the wood was dried up for up to three years without picking up the wood again to make the guitar. Let's look at various parts of an acoustic guitar.

Bridge Unit: This is most important part of guitar as the sound is generated here only. The bridge picks up the vibrations produced by strings (not the whole unit, but the part where the strings touch) and transmits it to the bridge unit, into the sound chamber. The vibration is then amplified using the chamber arrangement, bounced through the struts (they are fan-shaped for classical and box-shaped for acoustics), then pushed out from the sound hole.
In case plastic bridge is used, you must drop that guitar immediately. An ebony bridge works wonders on the guitar. Ebony is dense solid wood. However since ebony is expensive you could consider rosewood and ash. This unit is solidly glued to soundboard. This is why you need to make sure that you are buying a guitar with great bridge.

Body of guitar: If body of the guitar is made form plywood it's not a good guitar at all. An acoustic guitar is an extremely precise instrument. The front of guitar should be made of maple and the back panel is made form different kind of wood. Even though the wood is different, they should be mirror images of each other. If they are not, the guitar was not made by a good craftsman. The sides are also made from third kind of wood.

Some guitars are kept unvarnished. This is done as some people believe that guitar wood is reshaped over time as you start playing.

End block: The front and back of the guitar is joined using an end block. A dense wooden end block is good for guitar. Inspect guitar well and if the soles guy tell you not to, just walk away. Do not spend several hundred dollars on something that is not precise.

Neck of guitar:
Acoustic Guitars have a neck glued to the body. The neck needs to be installed only after the end block has been attached and the glue has been dried. The drying of glue should have happened several months before.

When you are buying a guitar, pay attention to whatever you have in front of you. Do not buy the guitar that's not made with precession. A good acoustic guitar has all the above characteristics. Acoustic guitar will give great music only if it has been crafted by a master craftsman not just any body.