Thinking for Orchestra, Practical Exercises in Orchestration by René Leibowitz, and Jan Maguire, is a method of teaching orchestration in two volumes, the first offering orchestral reductions with brief contents designed to help the student in scoring intelligently and the second having the composer’s orchestrations with further comments to compare with the students’s own.
Here you can find all the originally orchestrated examples of the second volume in audio format (zipped mp3) and in four virtual CD’s following the sections of the book:
I. The Classical Orchestra
II. Early Romantic Orchestration
III. Late Romantic Orchestration
IV. The Modern Orchestra