Since several of the classics of network research originated in Africa, further developments there might be eagerly awaited. However, the recent technological modernization of network studies has left most Africanists behind. Access to computers if often difficult to arrange and training higher mathematics is rare. Therefore, the works discussed here are in an older tradition, examining relationships of kin, neighbours and friends to see what they tell us about societal structure and the changes it is undergoing. Although networks are seldom specifically mentioned, three relevant themes often appear: social contacts as an index of social stratification; contacts between rural and urban areas, often symbolized by the maintenance of extended kinship networks, and the use of networks for political purposes. Several authors are concerned with more than one of these themes.

A segregation index is proposed which varies between +1 and -1 as against that proposed by Freeman which has a lower limit of zero even when links are concentrated in off-diagonal blocks. The distribution of the index is tested on 60,000 random networks. A simple chi-square estimates the departure from the null hypothesis of even distribution of links in diagonal and off-diagonal blocks. Some undesirable features of the proposed index are listed.

A separate index of systematic integration is introduced that seems to solve the problems raised by Mitchell (1978). Taken together with the segration index, this measure of integration permits the systematic examination of social links between two classes of people whether their observed cross-class links are over or underrepresented as compared to a random baseline.

Recently, we have been experimenting with the Small-World Technique (SWT), due to Stanley Milgram, in order to generate data on aspects of social structure. We feel that the SWT is a potentially powerful way to study social structure because it generates behavioral data. This review paper summarizes the available literature to date, and presents a program of related experiments which we are currently developing or wish others would do. In general, we hope that others will begin to study social structure experimentally.

Assimilation and integration, two major topics of ethnic studies, can be viewed from a network perspective, as the processes of migrants "plugging into" new types of networks. 1 Usually these processes consist of migrant or immigrant minorities' networks being "hooked up" to the majority networks. For many migrants there is much shifting and adding to a network web. But certain persons carry with them the frayed ends of the home village network which they cannot adapt in order to "plug into" the host-community urban nets, or else which host-communities are unwilling to accept.

The study of interorganizational relations has provided an arena in which the occurrence of network surrogates can be predicted using modern versions of order, numbers, ingroup-outgroup, and environmental-historical approaches. Predictive equations are provided, by way of illustration, for 104 of the largest cities in the United States. Isomorphism required departures from ubiquitous monotonic, linear and additive specification -- a warning against premature commitment to "content-free" methodologies.

Two conceptions of social structure may be distinguished: structural approaches analyze the patterns of relations among units, while distributional approaches seek to depict social structure through determining the distributions of characteristics of the units . Through explicitly developing the analytical method of constructing organized social forms from probabilistically conceived social actions, Weber systematically defined the aggregative and distributional logic which underlies much contemporary sociology. An examination of his studies of bureaucracy and of class and status, reveals that Weber abandoned his methodological strictures in favour of a more structural approach when his substantive and theoretical analysis required it. An understanding of the limitations of distributional conceptions of social structure points to theoretical and methodological approaches through which sociologists can build on both the distributional and the structural aspects of Weber's work.

This bibliography of recent work on corporate interlocking is prefaced by a modest technical-conceptual framework. The framework characterizes four types of studies . The studies differ on these characteristics: purpose, conceptualization of interlocking, choice of key agent, unit of observation, and data analysis technique.

For this first round-up I will attempt to broadly characterize the use of the social network concept in psychology. Delineating this topic is, quite appropriately, difficult. The areas of social network research in which psychologists are involved are thoroughly interdisciplinary. Moreover, some work done by psychologists does not involve variables that are particularly psychological in nature, and some work which does have a distinct psychological focus (e.g. avowed happiness, cf. Brim, 1974) is not done by psychologists. I will simply celebrate this condition, and not worry too much about the boundaries!

Some of the data from a "small world" study by Rochner, Buker and McLeod (1976) are reanalyzed to illustrate one of the difficulties in the statistical treatment of such social networks data. A conclusion reported in the original article is found to be incorrect and a new result is recorded.