In the interesting new book by Carslaw and Jaeger, Operational Methods in Applied Mathematics , a point is raised which does not seem to have been explained adequately in this or any other book on this subject that I have seen. This concerns the application of initial conditions to switching problems in electric circuit theory. Reference is made to this deficiency in a review of this book in the Gazette , XXVI, No. 268 (February 1942), pp. 63-64, and the present article is a suggested way of overcoming it.