an instructional guide to Essentials of college algebra," by W. L. Hart (1 l., 257 p.) consists of a selection from the author's College algebra, revised edition; "Plane and spherical trigonometry, by W. L. Hart (1 l., 217 p.) consists of selections taken with few changes from Plane trigonometry, solid geometry and spherical trigonometry, by W. W. Hart and W. L. Hart; "Analytic geometry," by W. A. Wilson and J. I. Tracey (1 l., 279 p.) gives the complete content of the authors Analytic geometry, alternate edition. cf. Pref.