**Down the river - Stage 3**: Longman Structural Readers are graded in six Stages according to the following principles:
1: The structures of the language are introduced in the same order as in the majority of modern course books. 2: The vocabulary is controlled as in other series, with the important development that words required for special purposes are included freely by a prescribed process of repetition.
The Handbook to Longman Structural Readers explains these principles in detail.
