Optical FiberTransmissionlSystems. By Stewart D. Personick. Pp. 179. Plenum, NewYork. 1981.$25.00.

The technology of optical communications has advanced at an astounding rate over the past decade with parallel developments in optical fibres and in optical sources and detectors. Several texts have been written dealing with the physics of such devices, but it is fitting that attention should now be given to the problems of system design and operation. Reliable components and associated devices are available-light emitting diodes, pulsed lasers, avalanche photo diodes, graded index and, more recently, monomode fibres. Dr Personick adopts a system engineer’s view of fibre optics for transmission based upon his intimate knowledge as one of the original workers in this new and exciting field.

This book is very readable and well pre- sented, reviewing briefly the fundamentals of multimode fibres, sources, and detectors in Chapter 1, followed by definitions for systems and sub-systems in Chapter 2, which inevit- ably contains elements of basic communica- tion theory-both digital and analogue-but set in an optical communications context. Chapter 3 on sub-systems includes an excel- lent description of noise and distortion in optical devices, whilst their combined effect on performance is brought together in the overall systems approach of Chapter 4. I found the final chapter on applications to be less satisfactory but the book as a whole can be recommended to the communications en- gineer and as a useful adjunct to an advanced course as one text in the Plenum series on ‘Applications of Communications Theory’.

John Lamb

ContemporaryAstronomy.2ndedition. By Jay Pasachoff. Pp. 545 + appendices. SaundersCollege Publishing, Philadelphia. 1981.$23.95(Teacher’s guide free).

This beautifully illustrated book, produced at an attractive price (by today’s standards), is intended for students with no background in mathematics or physics. It should also appeal to the general reader, young or old, who requires something more than a very basic text in astronomy.

In keeping with its title, Contemporary Astronomy places special emphasis on cur- rent research. For example, there are useful discussions of black holes and the interstellar medium. However, the author’s treatment of the Voyager missions to Jupiter and Saturn, although enlivened by a selection of the spectacular JPL photographs, is tantalisingly brief. A valuable feature of the book is the copious list of tables in the form of appen- dices. It is perhaps only to be expected that a book of this length should contain several errors, one of the more obvious being the solar ‘scale’ diagram (Fig. 7-19), which shows a penumbral shadow with parallel edges. Nevertheless, I can offer few major criticisms.

To summarise, Jay Pasachoff has written a fine book, which must surely rank among the

very best popular works on astronomy cur- rently available. Few readers can fail to absorb the author’s obvious enthusiasm for his subject.

F. R. Stephenson

MarineEnvironmentalPollution,Vol. 1 Hydrocarbons. Editedby R. A. Geyer. Pp.xix+ 591. Elsevier, Amsterdam. 1980. $117.00(Df/.240.00)

This book is a multi-author volume contain- ing 19 chapters. The coverage is very compre- hensive and will be of value to those in management as well as environmental re- search. The book is remarkable and re- freshing in that the majority of the chapters cover rather substantial topics or large geo- graphical areas and is thankfully rather thin on articles dealing with the effect of an oil spill on the distribution of a single species. The book is divided into two sections, the first dealing with the natural processes of release of oil into the environments, its distribution, and its decomposition or other fate. This half of the book in particular contains a collection of valuable and unique articles. The second section considers the impact of oil exploita- tion on the environment. Perhaps rather surprisingly, most of the articles in the second section deal with aspects of the environmental consequences of drilling muds. There are two especially valuable articles in the second section; one deals with world-wide status of research into the fate and effect of oil in the marine environment and the other deals with oil pollution in ice-covered waters.

P. J. Le B. Williams

The Lunar HighlandsCrust. Compiled by the Lunarandflanetarylnstitute, Houston, Texas, Pp, 505. Pergamon Press, Oxford. 1980. f26.00.

This is a Conference Proceedings of 23 pap- ers. The focal point is that part of the Moon’s crust that is pale-coloured and alumina-rich, densely cratered by meteorite impacts, and the source of the oldest measurable rocks. These ‘highlands’ debris-mountains contrast with the dark maria lowlands which are huge impact basins flooded by basalt lavas. A few highland rocks retain crystallisation ages of about 4,600 my but most have ages reset by basin-forming impacts around 3,900 my ago. Strong debate continues on the evolution of this primitive crustal assemblage.

The articles provide a view of the complex- ities involved in understanding how a planet- ary body behaved in its early evolutionary stages. That information is unavailable for the Earth, Mercury, and Mars. Ongoing and increasingly sophisticated lunar science holds much promise for important discoveries yet to be revealed by the treasure-store of Apollo samples still being investigated. Some articles review aspects of the science (rock classifica- tion, early genetic processes, cratering pro- cesses, highlands melt rocks, planetary crusts in general), but this aim is not apparent throughout. There is need for a more compre-

hensive review, with themes more strictly defined and inter-related. This book is a valuable first step in that direction.

G. M. Brown

CosmicX-ray Astronomy. ByD. J. Adams, Pp. x+ 150. Adam Hilger, Bristol. 1980. f 13.50.

It is puzzling that the new branches of obser- vational astronomy, which have produced so many dramatic and exciting discoveries, should be so poorly served by textbooks. Radioastronomy, despite having been estab- lished for more than forty years, still has very few student texts and this book by David Adams is probably the first attempt, in X-ray astronomy, at a book for the student rather than the specialist. The book is divided into five sections, the first two dealing with observ- ing techniques and with astrophysical mechanisms for the production of X-rays, and the final three with the observations of binary X-ray sources, supernova remnants, and ex- tragalactic sources. The publishers claim that the treatment of the subject makes the book suitable for the amateur astronomer, but the reader does need a familiarity with physics, particularly in the section dealing with the production of X-rays. There is a good selec- tion of references which will allow the keen student to follow the subject further, although most of the journals cited are prob- ably not available outside University librar- ies. A subject which is still in its pioneering stage is always difficult to structure, but the author has selected his material well and has set a standard for later textbooks to follow.

R. R. Hillier

TheCosmicConnection. byCarlSagan. Pp. 274. Macmillan, London. 1981. Paperback f2.95.

The Cosmic Connection represents an earlier attempt by Sagan to popularise astronomy before his current book and television series, Cosmos. The show business approach is already there (though the book is said to be ‘by Carl Sagan’, it is also, mysteriously, ‘produced by Jerome Agel’), but is less obtru- sive than in the more recent production. We are given a large number of short chapters, each with an intriguing title-‘Venus is Hell’; ‘Cables, Drums and Seashells’; and so on. The topics are dictated by Sagan’s own in- terests: the main theme is life in the Universe, with particular emphasis on the space ex- ploration of the planets.

In trying to capture the reader’s attention, Sagan sometimes overdoes the flamboyant statement. He claims, for example-‘1 know a sun the size of the Earth-and made of diamond’. Does he really mean ‘diamond’, or is this a more gripping (but less accurate) way of saying ‘carbon’? On a broader front, any reader of this book might be forgiven for supposing-incorrectly-that the existence of planets elsewhere in the Universe is now firmly established. Another drawback is that the material dates back to 1973, and space

41