Bookcase cabinets can vary in size, design, and function, so before you head out to the furniture store to purchase one, you will need to determine what your needs are for space, aesthetics, cost, and so on. It helps to measure the space in your home where you intend to place the unit, and it also helps to draw up a budget for purchasing bookcase cabinets. If you need more than one unit, be sure to plan where each one will go to avoid clutter and access problems. Think carefully about the materials used to make such a bookcase as well.
The materials used to make bookcase cabinets will have perhaps the biggest impact on how much the unit costs as well as how durable it will be. Wood bookcase cabinets are the most common because woods tend to be naturally beautiful and durable in many cases, depending of course on which type of wood is used. Research the different types of wood to find out which one will fit your aesthetic needs the best; hardwoods tend to last longer and age better, and woods such as teak and cedar are resistant to moisture damage and mold buildup, so if the room tends to be moist, these might be good choices.
Consider the designs of the bookcase cabinets to find the one that will be the most functional for you. Cabinet doors can be solid, or they may be open and glassed. Glass doors allow you to see into the cabinet even when the doors are closed, providing a pleasing aesthetic as well as the convenience of being able to find a certain book without having to open the doors. Be sure to measure how large the doors are; when open, they may interfere with other furniture or objects in a room, so it is best to consider this before purchasing.
Regardless of the style of bookcase cabinets you choose, be sure the units are stable and well constructed. Be sure to try to move the unit to see if it wobbles, creaks, or otherwise indicates it may not be stable or solidly constructed. Inspect the shelves within to find out if they are adjustable or fixed, and make sure they are stable when loaded with weight. Inspect the joints of the bookcases to ensure they are properly secured and aesthetically pleasing. The joints will give you some indication of the quality of workmanship from the builder.