Courtesy of Christianbook.com:
Simulated or Imitation Leathers
"Simulated Leather", "Imitation Leather", "Leather-look", "LeatherLike" and "Leatherflex" Bibles all have a leather appearance but may be made from a variety of materials. These materials are then coated and embossed to give them a leather-like quality. These covers are slightly more durable than a paperback but not as durable as bonded leather.
In recent years, many publishers have come out with some very nice "imitation leathers" which should prove to be close in durability to bonded leather, but they haven't been on the market long enough to know for sure. Some of these better quality imitation leathers go by such names as "Tru-Tone," "TuTone," "Duo-Tone" and the like.
"Bonded Leather" is made from real leather. However, as the name suggests, the cover is made from leather pieces that are bonded together with latex. Once bonded, the leather is dyed, cut and embossed to look like genuine leather. The look and feel is as genuine leather (though not high-grade leather). Due to the fact that it is not made from a single sheet of leather, bonded leather is less expensive, and more often than not, less durable than genuine leather.
"Berkshire Leather", "Genuine Leather", "Top-Grain Leather", "Cowhide", and "Morocco Leather" differ from Bonded Leather in that they all consist of a single piece of leather, not many bonded pieces. With proper care, these covers could last indefinitely.
"Berkshire Leather" is high quality pigskin. It is tanned to enhance its appearance and durability.
"Genuine Leather" is made from first quality animal hides (usually pig or cowhide). It has a finely grained texture, which is thicker and coarser than Top-Grain Leather.
"Top-Grain Leather" is cut from the top or outside of the hide and consists of Pigskin or cowhide. Its grain is thicker and coarser than Cowhide.
"Cowhide" is cut from either cattle or water buffalo. It has a finer and suppler grain, which is slightly more durable than Top-Grain leather. As a result, it is more expensive.
"Morocco" is high quality leather made of imported goatskin, usually worked by hand. It is considered to be one of the finest binding leathers. As such it is very durable and expensive.