The broad aim of SUBCELLULAR BIOCHEMISTRY is to present an inte­ grated view of the cell in which artificial barriers between disciplines are bro­ ken down. The contents of Volume 7 illustrate the interconnections between initially unrelated fields of study and show strikingly how advances along one front become possible because of parallel successes in another. Current research into cell organelles and membrane systems is not only concerned with the elucidation of their structure and function. It also asks such questions as: Which regions of the cell are concerned in the bioassembly of the organelle? How are organelle and membrane precursors transported from the site of syn­ thesis to the newly formed cell constituent? What genetic systems control the biosynthesis and assembly of cell components and how do these systems inter­ act? How did the various cell constituents evolve? How did the genetic and biosynthetic systems making the organelles themselves evolve? The search for the answer to such questions has placed organelle biochemistry on a different level than that of the more restricted studies of the 1950s and early 1960s and promises to produce some fascinating and surprising results. Volume 7 opens with a detailed chapter by A. A. Hadjiolov on the bio­ genesis of ribosomes of eukaryotes. The general arrangement of ribosomal genes is discussed, and there is a full account of their transcription.