Chapter 1: Microbial World: A Treasure of Secondary Metabolites (Seema Singh, Ambika, Charul Kainthola, Nidhi Gupta, Abhishek Kumar, Amit Pandey) Chapter 2: Microbial Strains as a Factory for Valuable Secondary Metabolites (Mukta Sharma, Atul Singh, Anandveer Singh Sindu) Chapter 3: Industrial Applications of Microbial Secondary Metabolites: Diversity, Classification, and Sources (Moti Lal, Neelam) Chapter 4: Exploring Microbial Diversity for Secondary Metabolite Production: A Metagenomic Approach (Ashwini A. Waoo, C. Vyas, B.A. Chopade) Chapter 5: Biomolecular Microbial Metabolism and Microbial Secondary Metabolites Production Pathways (Yogitha N. Sagar, Nitya Mankal, Senthilkumar R, Ankita Chatterjee), Chapter 6: Enzymes for Microbial Secondary Metabolite Production (H. Pandey, Prakasha, R) Chapter 7: Sustainable Agriculture and Microbial Secondary Metabolites (Shalini Fagna, Apexa Pareek, Payal Lodha) Chapter 8: Beneficial Microbe-Induced Secondary Metabolites: Interactions with Plants and Soil Microbiome (Anandkumar Naorem, M. Chandra Surya Rao, Devi Shidayaichenbi, Saranya R.) Chapter 9: Viral Secondary Metabolites and Their Applications (T. Attri, A. Sharma, M. Sharma) Chapter 10: Various Bacterial Secondary Metabolites and Their Roles in Basic Metabolic Processes (Jyoti Lodhi, Monu Ashutosh Shukla) Chapter 11: Potential Strategies for Fungal Secondary Metabolites-Based Mycoherbicide Development to Control Invasive Weeds: An Eco-Friendly Weed Control Option for Sustainable Agriculture (A.K. Singh, A.K. Pandey) Chapter 12: Host-Specific Fungal Toxins: Status and Perspectives (Jaya Singh, Saurabh Gupta), Chapter 13: Mycorrhizal Secondary Metabolites: An Overview (Avinash Kumar Chaurasia, Ritika Kumari Singh, Riden Saxena, Kriti Shrinet) Chapter 14: Arbuscular Mycorrhizal Fungi-Plant Interaction for Salinity Stress Alleviation (Priyanka Chandra, Arvind Kumar Rai, Parul Sundha, Nirmalendu Basak, Sandeep Bedwal, Rajender Kumar Yadav) Chapter 15: Endophytes: Enormous Source of Novel Bioactive Secondary Metabolites (Jyoti Bhagat, Amarjeet Kaur, Priyanka Chandra) Chapter 16: Algal Secondary Metabolites: An Overview (Shreya Kapoor, Sakshi Verma, Sneh Priya, Aishani Gupta, Vandana Gupta) Chapter 17: Unlocking the Potential of Algal Secondary Metabolites (Renu Sharma, Tara Maheshwari, Apexa Pareek, Payal Lodha)Chapter 18: Microalgae as a Sustainable Source of Value-Added Secondary Metabolites (Manisha Bisht, Pramod Rawat, Yashaswi Singh, Manoj Pal) Chapter 19: Functional and Nutritional Potential of Freshwater Microalgae: An Eco-friendly Solution to Global Food (Neetu Mishra, Neha Mishra) Chapter 20: Marine Microbial Secondary Metabolites: An Overview and Importance (P. Trapti) Chapter 21: The Promise of Marine Microbiome: Exploring the Functional Dynamics of Secondary Metabolites from Marine Origin (Prabha Susan Philip, Sneha S. Nair).