It’s not very comprehensive, so it’s best for beginners. But I don’t consider myself a beginner and I use it all the time.  For every entry, there is a short definition, followed by a few sentences so you can see the word in action! Even for advanced students this can be a lot easier than trying to make sense of phrases like “что на что кому чего” that are given in most dictionaries.

If you like the smell of used books as much as I do, pick up a copy for under $5.00 at Amazon.com. (New copies also available.)