a book that contains detailed information about a subject for people who are studying that subject

a science textbook 自然科学教科书

(of an example of something) extremely good, or thought to be usual or typical

That was a textbook goal from Taylor. 泰勒那个进球堪称典范。

It was a textbook example of how to deal with the problem. 这是如何处理此问题的一个范例。