There are different kinds of 'dictionaries' that you can use. They can go greatly into detail about each artist, like the Oxford Dictionary of Art volumes or even encyclopedias on art. This one is for the really basic information; you'll see that Mondrian worked in the early 20th century and was a member of the De Stijl movement so you can take that information and go do more research elsewhere. It's good for very basic referencing and understanding. I prefer Thames and Hudson's Dictionary of Art and Artists, it's very similar to the Penguin dictionary but has a little bit more substance to each entry which I prefer.
i loved flipping through this girl. makes me feel sad that i dont have apah anymore but it will live on forever in my heart. i can feel the knowledge slipping awayyyy
A perfectly fine reference book that Wikipedia made largely obsolete ten years ago, unless you're trying to memorize a lot of basic facts about artists in a hurry. Also, it's twenty years old, so don't look for anything about the current art scene.
A good little reference book. I used it for art history papers in school. The entries are short but concise. It is an older book so it doesn't have anything past pop art.