A language learners’ forum

I have a fantastic Russian grammar book with lots of exercises, but unfortunately it has no answer key, and there doesn't seem to be one available online or for purchase. What would be the best way to make use of this book?

Stick your answers up on italki, Lang-8, or LingQ and get them corrected. Alternatively go though the material with a tutor.

It depends on the kind of exercise. For some of them, it suffices to type the sentence to google (the normal browser, not google translator), and see what it returns to you. If the sentence exists, it has probably been used with some small variation already, or the key feature you are practicing is something people have already been asking about, or it will point you to an example on a grammar website. For some others, Italki is a good choice, Lang8 doesn't let people sign up now.

But I agree it sucks not to have a key to exercises. It takes way too much time without such a key.

Basically what neofight78 said, but if you mention the name maybe someone can find it.

Another way to use it, unless you're just particularly taken with grammatical exercises, is just to use the book as a source of sentences for SRS or GoldList or whatever you use. Most grammatically-focused books have lots of L2 sentences with L1 translations which you can use to internalize the grammar patterns. Obviously, of course, even using this approach, it's better to have the answers, because this usually gives you even more sentences.

You can use it to prop a wobbly table.