This is not sturdy for the heavy reference books I use but the angle is adjustable and the ledge for the books is deep enough. If the book slips the tabs holding it in place will snap off. But for the price I really didn't expect more.
I was afraid to buy this due to being made out of plastic. Great product for adult children and older. Small children may break holders off if they are rough. This saves your neck from looking down so much keeps better posture for your back.
The only reason I didn't give this five stars is that it's a little tricky to adjust the height to its top setting. Once set however the book holder is great! It's so nice not to have to go from looking straight ahead (at my computer screen) to down at my desktop (in front of behind or beside my keyboard) and back again repeatedly!