WHICH EDITION OF THE TEXT?

This is the first year that the 4th edition of Stewart's calculus text is being used for MTH 255. There is very little difference between the 3rd and 4th editions so far as vector calculus is concerned. Officially, you should have the 4th edition. In practice, you can get by with the 3rd.
The required texts are:
James Stewart, Calculus, 4th edition
Tevian Dray, Calculus Study Guide -- MTH 255

Below is the basic translation between the editions.

Study Guide 3rd Edition 4th Edition
Early Transcendentals
4th Edition
Multivariable
Lesson 1 §11.7 §13.1-§13.2 §14.1-§14.2
Lesson 2 §11.8-§11.9 §13.2-§13.4 §14.2-§14.4
Lesson 3 §12.6 §14.6 §15.6
Lesson 4 §12.7 §14.7 §15.7
Lesson 5 §12.8 §14.8 §15.8
Lesson 6 §14.1 §16.1 §17.1
Lesson 7 §15.2 §16.2 §17.2
Lesson 8 §14.3 §16.3 §17.3
Lesson 9 §14.4 §16.4 §17.4
Lesson 10 §14.5 §16.5 §17.5
Lesson 11 §13.9 §15.9 §16.9
Lesson 12 §14.6 §16.6 §17.6
Lesson 13 §14.7 §16.7 §17.7
Lesson 14 §14.8 §16.8 §17.8
Lesson 15 §14.9 §16.9 §17.9