4 – A. K. T. Assis and J. A. Hernandes, "The Electric Force of a Current: Weber and the Surface Charges of Resistive Conductors Carrying Steady Currents" (Apeiron, Montreal, 2007), 239 pages, ISBN: 9780973291155. Book in PDF format (5 Mb): http://www.ifi.unicamp.br/~assis/The-Electric-Force-of-a-Current.pdf. Preface by Hermann Härtel. Errata. This book can be ordered from Amazon: http://www.amazon.com/dp/097329115X and at Barnes and Noble: http://www.barnesandnoble.com Reviews of this book: (A) J. Fukai, Note de Lecture, Annales de la Fondation Louis de Broglie, Vol. 32, pp. 557-558 (2007); (B) L. Hecht, Wilhelm Weber defended, 21st Century Science & Technology, Fall 2007, p. 72; (C1) H. Torres-Silva, Review of book, Ingeniare, Revista Chilena de Ingeniería, Vol. 16, pp. 273-274 (2008); (C2) H. Torres-Silva, Reseña de libro, Ingeniare, Revista Chilena de Ingeniería, Vol. 16, pp. 275-277 (2008); (D) H. Härtel, Buchbesprechung, Mitteilungen der Gauss-Gesellschaft, Vol. 45, pp. 122-123 (2008).