New concept english
新概念英语

There is no such book.
It depends upon the age group, the prior English instruction and the current English capability.

There is no book where one size fits all.

Further, every person learns differently and that is why there are so many books and programs available.

The question is simplistic but does not invite a similar response.

Martin is right, though he comes across as somewhat of an ass in his answer!

The truth is, the first thing you have to do is evaluate your class in terms of age group, class size, ability and material at your disposition.

For smaller kids, you want textbooks with lots of pictures, lots of games, and usually one vocab, one grammar, one reading and one pronunciation section for each lesson.

For older kids, good luck would be my first word, but in general they're not ALL that different from the young kids. They want games. It just needs to be suited to their needs, with interested conversations, group activities, etc...

Finally, for adults, you'll probably want something especially tailored to their needs. Is it basic English, business, etc...

If you're really speaking in broad terms, I've found the Let's Go series good for younger kids.

Here's a link to a forum about books on the best teaching website there is...

I agree with others, basically there isn't one! But there are generally accepted ones across China that Parents like to see their kids use. They are mostly published by cambridge press or Longman pearson, such as Interchange, BEC, New Concept, Oxford English ( primary and Middle School ) and another one that i can't remember but has a character called "Daming" in it. In my current job and previous i was given books and never used them, just took ideas from them and designed classes around them, especially for conversational English.

I often use Malcolm Gladwell's Outliers: The Story of Success.