For aspirants of UPSC, it is a moderately popular subject.
I recommend it as an optional for UPSC only to those who have the ability to think critically beyond the obvious and model abstractions, especially in paper-I. Not that those who consider themselves challenged in this respect cannot prepare for this optional, but those who can will have a decisive advantage. Study Material for paper-II is not found easily, and the understanding of key concepts of Paper-I and ability to apply them to real life situations comes in handy.
Here's my recommended Booklist for Socio:-
1)Haralambos - The Bible. (Though this book seems easy, do not not take it lightly.You will find yourself going back to it again and again. Make clever use of real life studies in the book to substantiate your answers)
2) Mahapatra ( Vajiram) Sir's Class notes
3) Sociological Thory by Ritzer. (hard to find but gives a good account of theories)
Caution: - Do not study Bottomore (Useless). Refer to Ignou Material ( MSO notes) for only topics that you can't find in above.
For Paper-II, I have edited the booklist provided here.
A. Introducing Indian Society:
(i) Perspectives on the study of Indian society : Indian Sociological Thought. from B. K. Nagla
(b) Structural functionalism (M N Srinivas).
(c) Marxist sociology ( A R Desai).
(ii) Impact of colonial rule on Indian society :
(a) Social background of Indian nationalism. Mahaptra Sir's Notes
(b) Modernization of Indian tradition. Modernization of Indian tradition - Yogenndra Singh,Handbook of Indian Socio by Veena Das
(c) Protests and movements during the colonial period. Protests and movements during the colonial period – A R Desai
(d) Social reforms Spectrum's Indian
B. Social Structure:
(i) Rural and Agrarian Social Structure:
(a) The idea of Indian village and village studies- IGNOU ,Handbook of Indian Socio by Veena Das
(b) Agrarian social structure – evolution of land tenure system, land reforms. Praveen Kishore (Inspiration's) study material
(ii) Caste System:(a) Perspectives on the study of caste systems: GS Ghurye, M N Srinivas, Louis Dumont, Andre Beteille. – Indian Sociological Thought. from B. K. Nagla
(b) Features of caste system. ( Summarize the perspectives from previous topic)
(c) Untouchability – forms and perspectives Praveen Kishore (Inspiration's) study material
(iii) Tribal communities in India: Indian Society & Culture – Nadeem Husnain
(a) Definitional problems. Indian Social System – Ram Ahuja
(b) Geographical spread.
(c) Colonial policies and tribes.
(d) Issues of integration and autonomy.
(iv) Social Classes in India: – IGNOU
(a) Agrarian class structure.
(b) Industrial class structure.
(c) Middle classes in India.
(v) Systems of Kinship in India: - IGNOU
(a) Lineage and descent in India.
(b) Types of kinship systems.
(c) Family and marriage in India.
(d) Household dimensions of the family.
(e) Patriarchy, entitlements and sexual division of labour.
(vi) Religion and Society: Praveen Kishore (Inspiration's) study material
(a) Religious communities in India.
(b) Problems of religious minorities.
C. Social Changes in India:
(i) Visions of Social Change in India:
(a) Idea of development planning and mixed economy. – Contemporary India – Neera Chandhoke
(b) Constitution, law and social change. – Social Change in India – Yogendra Singh,Modernization of Indian tradition - Yogenndra Singh
(c) Education and social change. – IGNOU , ESO – 14, – Social Change in India – Yogendra Singh,Modernization of Indian tradition - Yogendra Singh
(ii) Rural and Agrarian transformation in India:
(a) Programmes of rural development, Community Development Programme, cooperatives, poverty alleviation schemes - Praveen Kishore (Inspiration's) study material
(b) Green revolution and social change - Praveen Kishore (Inspiration's) study material
(c) Changing modes of production in Indian agriculture - Paper by Hamza Alavi
(d) Problems of rural labour, bondage, migration. IGNOU , MSO – 14
(iii) Industrialization and Urbanisation in India: IGNOU
(a) Evolution of modern industry in India.
(b) Growth of urban settlements in India.
(c) Working class: structure, growth, class mobilization.
(d) Informal sector, child labour Handbook of Indian Socio by Veena Das
(e) Slums and deprivation in urban areas. IGNOU
(iv) Politics and Society:
(a) Nation, democracy and citizenship.
(b) Political parties, pressure groups , social and political elite.
(c) Regionalism and decentralization of power.
(v) Social Movements in Modern India: Social Movements In India by Ghanshyam Shah
(a) Peasants and farmers movements.
(b) Women’s movement.
(c) Backward classes & Dalit movement.
(d) Environmental movements.
(e) Ethnicity and Identity movements.
A book on National & Social Issues by Smarak Swain, IRS is highly recommended for topics against which I have not mentioned any book and also to understand how to make notes in Sociology.It also contains excellent write-ups on topics on which I have already recommended some book.
(vi) Population Dynamics: Social Demography : Asha Bhede & Kanitkar
(a) Population size, growth, composition and distribution.
(b) Components of population growth: birth, death, migration.
(c) Population policy and family planning.
(d) Emerging issues: ageing, sex ratios, child and infant mortality, reproductive health. : IGNOU (ESO – 16 )
(vii) Challenges of Social Transformation:
(a) Crisis of development: displacement, environmental problems and sustainability.
(b) Poverty, deprivation and inequalities.
(c) Violence against women. Women in India – Neera Desai
(d) Caste conflicts. Politics in India : Sudipta Kaviraj
(e) Ethnic conflicts, communalism, religious revivalism. IGNOU (ESO – 16 )
(f) Illiteracy and disparities in education. Handbook of Indian Socio by Veena Das
Caution: - Stick strictly to syllabus while referrring to any of the book above, and preferably make your own notes ( detailed or short) to save time during revision.
Tips: Pick up a topic, scan all sources, collate them logically to make your own notes. You should do this atleast for paper-II in sociology, though it works well for all subjects, atleast for me.