Refractors use lenses to produce the image, reflectors use mirrors. Refractors are the more traditional-looking telescopes. This is the kind of telescope that we can literally look through . There is a lens at the front of the tube and an observer looks through an eyepiece at the other end. Refractors are generally rugged instruments that require no adjustments to the optics.
Reflectors bounce the image off of a large primary mirror in the back.
The variety of reflector known as Newtonian also uses a flat secondary mirror to bounce the image through the eyepiece located on the side of the tube. These telescopes offer the largest apertures and generally cost less than refractors of comparable aperture size. On the negative side, however, the optics do require occasional adjustments. Also check out your local library and bookstore.