Practical and easy
The Teach Yourself collection has always been the best help for me when it comes to learning languages. Regular grammars by themselves, while very specific and correct, can become somewhat boring, and even difficult to understand, pulling out things that we don't even remember in our own language anymore sometimes - noun, adverb, complement, adjective... Teach Yourself Estonian is all I am using to learn the language, besides a handy dictionary and a few helpful websites. It keeps it clean and simple, really easy to understand, with plenty of examples and many exercises for you to evaluate your own development. I wouldn't expect anything else from a Teach Yourself book, and so far I am not disappointed.