這篇論文包括四個主題：（一）何謂社會資本？（二）社會資本理論為何？（三）如何測量社會資本？（四）有關社會資本研究的例子。本文全圖從馬克斯的資本論、經濟學家的人力資本論與文化資本論，來區別「社會資本」概念定義。林南社會資本理論主張社會資本是鑲嵌於人際關係與社會網絡的資源，也是一種關係投資。社會資本的投資有以下命題：人們投資社會關係具有結構限制和行動選擇性，選擇的資源是越多元豐富越好。投資的行為有兩個層次：可接觸的社會關係資源的能量(capacity)，資源的運用化(utilization)；社會資本理論也關懷工具性和情感性報酬效應。社會資本的測量是在衡量社會資本的能量，使用「定位法(position generator)」，亦即將社會上不同意義與價值的位置作為連結社會關係的生產者，社會資本的建構與效應也是社會資本測量與分析的核心重點。最後本文舉出林南使用社會資本理論與概念所從事的研究案例：求職的鎖鏈、找工作時無形的幫手、社會網絡與社會參與組織對社會資本的需求、臺灣、中國與美國的社會資本比較研究。

This paper covers four key subjects: (1) How to conceptualize social capital? (2) What is the theory of social capital? (3) How to measure social capital? (4) And, it introduces researches on social capital. This article tries to distinguish the concept of social capital from the concept of capital as defined by Marx, the human capital defined by economist and the cultural capital. Nan Lin's theory of social capital stresses that social capital includes social resources which are embedded in interpersonal relations and social networks, and are also an investment in social relations. The propositions regarding social capital are as it follows: The investments in social relations are structurally constrained and contain choices of actions. The more diversified resources individuals can access, the better. There are two dimensions of investment behaviors: the resource capacity of accessed social networks and the resource utilization. Social capital theory is also concerned with the instrumental and expressive return of the network investment. Finally, Nan Lin puts emphasis on the measure of the capability of social capital and uses the method of position generator to collect network data. The position generator uses a series of ranked position to generate social contacts, that is to say individuals who know people who are in that position. Both the creation and Return of social capital are the major parts of social capital analyses.