Fourteen years have passed since the publication of David Spencer Smith's Insect Cells: Their Structure and Function. Here the results of a decade of electronmicroscopic studies on insect cells were summarized in an organized and integrated fashion for the first time, and the ultrastructural characteristics of different specialized cells and tissues were abundantly illustrated in the 117 plates this monograph contained. In the intervening period great progress has been made in the field of Insect Ultrastructure. Organelles not even mentioned in Smith's book, such as synaptonemal complexes, clathrin baskets, fusomes, and retinular junc tions, have been identified and functions proposed for them. There have also been many technical advances that have profoundly influenced the direction of subsequent research. A spectacular example would be the development by Miller and Beatty of the chromosomal spreading technique which allowed for the first time ultrastructural studies on segments of chromosomes containing genes in various stages of replication and transcription. Then there is the freeze-fracture procedure first described by Moor and his colleagues. This technique permitted an analysis of intercellular junctions that was impossible with the conventional sectioning methods. The results greatly clarified our understanding of the channels for ion movement and the permeability barriers between cells and also the membrane changes that occur during the embryonic differentiation and metamorphosis of various types of insect cells."

Cell biology is moving at breakneck speed, and many of the results from studies on insects have helped in understanding some of the central problems of biology. The time is therefore ripe to provide the scientific community with a series of up-to-date, well illustrated reviews of selected aspects of the sub microscopic cytology of insects. The topics we have included fall into four general groups: seven chapters deal with gametogenesis, four concern develop ing somatic cells, seventeen chapters describe specialized tissues and organs, and three chapters cover cells in pathological states. These accounts are illustrated with over 600 electron micrographs. The more than 1100 pages in the two volumes of Insect Ultrastructure combined labors of 49 dedicated contributors from II countries. represent the These authors have digested and critically summarized a very large body of information, and some measure of this effort can be gained from consulting the bibliographies that close each of the 31 chapters. These contain 2400 publica tions authored by 1500 different scientists. However, before we congratulate ourselves on the advanced state of our knowledge, it is worth remembering that representatives of less than 0.01 % of the known species of insects have been examined with the electron microscope.