with the subjects. Ten are scientists

who remained in academic research

and the rest are scientists who left;

each group is evenly divided by sex.

These chapters are very important,

since they give life to the findings and

illustrate the interaction of deficits and

differences in real careers.

Most young scientists, both men and

women, will find the chapter of advice

in Who Succeeds in Science? very use-

ful. The chapter on policy is also ex-

cellent and confronts the question of

whether women should be encouraged

to go into science at a time when the

job market is so tight and no reliable

prediction can be made of the need for

scientists in the future.

VERA KISTIAKOWSKY

Statistical

Thermodynamics

of Surfaces, Interfaces,

and Membranes

Samuel A. Safran

Only recently has soft condensed mat-

ter physics—an area dealing with such

diverse materials as polymers, am-

phiphiles, liquid crystals and mem-

branes—been recognized by the phys-

ics community as an area of study in

its own right. The materials embraced

share a tendency to self-assemble into

aggregates such as lamellae and cylin-

drical or spherical micelles. These ag-

gregates may themselves assemble,

producing either ordered phases whose

symmetries range from the pedestrian

to the bizarre or disordered fluids

whose structures range from the trivial

to the complex.

The growth of interest in this non-

traditional area is fed not simply by

the inherent interest of such systems

but also by their enormous technologi-

cal importance and the increased

stimulation arising from the area's

overlap with biological subdisciplines.

Indeed, the model of biological mem-

branes as a bilayer ofamphiphilic phos-

pholipids, undergirded by an elastic

network of specialized proteins (them-

selves polymers of amino acids) and

incorporating other biologically active

proteins, serves as a paradigm of the

overlap of interests. This intersection

of physics, chemistry, biology and ma-

terials science is most likely to be one

of the areas of greatest excitement and

growth in the next decade.

A small indication of the activity in

this field was the publication in late

1994 of three books on the subject,

including Samuel Safran's Statistical

faces, and Membranes. All three deal

with similar material but each presents

it very differently and to a somewhat

different audience. The other two

books are the multiauthor collection

and Monolayers, edited by William Gel-

bart, Avinoam Ben-Shaul and Didier

Roux (Springer-Verlag) and the mono-

graph Self-Assembling Amphiphilic

Systems by Gerhard Gompper and me

(Academic) (See PHYSICS TODAY, March

1995, page 91). Whereas the latter two

are more narrowly intended for re-

searchers and their students, Safran's

book is broadly targeted at first-year

graduate students in any number ofdis-

ciplines and assumes only a rudimentary

knowledge of statistical mechanics.

One of the most laudable aspects of

Safran's presentation is the methodical

way he proceeds from simple to com-

plex systems. He first considers a sin-

gle isolated and static interface. The

effects of thermal fluctuations on the

interface are then considered in a dis-

cussion that culminates in a particu-

larly simple variational treatment of

the roughening transition first given

by Yukio Saito. Interactions between

rigid interfaces are considered next. I

was surprised and pleased to find here

a nice presentation of the theory of van

der Waals interactions due to Igor

Dzyaloshinskii, Evgenii Lifshitz and

Lev Pitaevskii; such a presentation is

unusual in a book aimed at beginning

graduate students. Fluctuations are

then added to the interfaces, which

leads to the discussion of bending en-

ergies and curvature moduli. This sec-

tion provides a nice example of the

benefits of a well-thought-out incre-

mental approach. Having previously

calculated the pressure between

charged plates immersed in solvent,

Safran can now use it to obtain the

saddle-splay modulus of a collection of

charged membranes. Finally, systems

of extensive amounts of interface are

treated, starting with colloids, whose

surfaces are given and rigid, and con-

cluding with self-assembling systems

consisting of fluctuating interfaces, as

exemplified by microemulsions.

While the systems studied get pro-

gressively more complex, the methods

employed do not. Safran consistently

applies variational methods wherever

possible. If this approach causes him

to sacrifice a treatment of the Koster-

litz-Thouless recursion relations when

discussing roughening, it nonetheless

enables him to tie this discussion to a

later one devoted to fluctuations in

bicontinuous phases. The presenta-

tion also benefits greatly from stimu-

lating and challenging problems.

The book has one major weakness:

There is almost no discussion ofexperi-

ment or its connection to theory. Were

I to teach a course using Safran's book,

I would certainly have to supplement

it with much discussion of physical

phenomena. Following my own preju-

dices, I would also broaden the cover-

age of the last chapter on self-assem-

bling systems, which now builds only

on the elastic description of interfaces

in earlier chapters, to include a Landau

description, which would also use

methods presented earlier. But it is a

tribute to this delightful book that,

after reading it, I would like to teach

a course based upon it. And I would

advertise it widely, not only in my own

department, but in biology, chemistry

and materials science as well.

MICHAEL

ScracK

Optical Coherence

and Quantum Optics

Leonard Mandel and Emil Wolf

Optical coherence theory underlies im-

age formation for naturally illuminated

and self-luminous scenes, wave propa-

gation and scattering in random media,

and all forms of optical interferometry.

The purview of quantum optics spans

laser theory, photon and photoelectron

statistics and fundamental issues in

quantum measurement.

Optical coherence and quantum op-

tics have long been closely related.

However, the breadth and depth of

knowledge that exist in these two fields

make attempting their thorough cov-

erage in a single volume a daunting

task. In Optical Coherence and Quan-

tum Optics, Leonard Mandel and Emil

Wolf have made a worthy effort toward

that end; it helps that the authors'

names are nearly synonymous with the

book's title.

In essence. Optical Coherence and

Quantum Optics is three books: one on

the propagation of classical field coher-

ence functions in free space, one on

laser theory and related topics and one

on photodetection and nonclassical

light. Although Mandel and Wolfbuild

connections among these topics, divid-

ing the book into three units can be

accomplished without much loss ofcon-

tinuity or content.

The discussion of coherence theory

for classical fields commences with ele-

mentary, semiquantitative assessments

68

MAY 1996

PHYSICS TODAY