Kallen's Quantenelektrodynamik provides a concise treatment of the subject. Its strong points are the careful attention to ex­ planatory detail, the methodical coverage of all the maj or results and the straightforward, lucid style. Certainly it will be a val­ uable reference for one learning the subject or for one who re­ quires the details of the practical results. Of course modern quantum field theory has now grown far beyond its dramatic be­ ginnings in electrodynamics and we have therefore included some references to introduce the reader to the more recent and more specialized literature. We have corrected some minor errors: we would appreciate it if readers would inform us of any others which they find. We thank Professors Paul Urban and C. MtSller for permission to use the biographical material on Kallen. We also wish to thank Springer-Verlag for undertaking publication of this edition by an unorthodox method, but one which will reduce the cost to the reader. In particular, we are grateful to Dr. H. Mayer-Kaupp and Mr. Herb Stillman for their kind cooperation. Finally, we thank Mr. Michael Teague for reading and commenting on the first dozen sections and we thank Mrs. Joanne Downs for ed iting and typing the final manuscript. May 1972 C. K. Iddings M. Mizushima Department of PhysiCS and Astrophysics University of Colorado Boulder, Colorado 80302 .. ., IN MEMORIAM PROFESSOR GUNNAR KALLEN On October 13, 1968, Professor Gunnar Kallen of the University of Lund, Sweden, died in an airplane accident near Hanover.