Arbuscular mycorrhiza (AM) are crucial symbiotic associations formed between arbuscular mycorrhizal fungi and the roots of various plant taxa, including pteridophytes and gymnosperms. This symbiosis enhances nutrient uptake, particularly phosphorus, improves plant stress resilience, and promotes soil health and biodiversity. The diversity of AM fungi associated with these non-flowering vascular plants is significantly influenced by environmental factors, host plant species, and community interactions. Research demonstrates that AM fungal diversity can vary widely among pteridophytes and gymnosperms, impacting their growth and ecosystem functions. Understanding these intricate plant-microbe interactions is vital for advancing ecological restoration efforts and sustainable agricultural practices, especially in nutrient-poor soils. It explores the complex relationships between arbuscular mycorrhizal fungi and non-flowering vascular plants, highlighting the significant role of AM fungi in enhancing nutrient uptake, promoting plant growth, and contributing to soil health. The book discusses the diversity of AM fungi associated with pteridophytes and gymnosperms, examining how environmental factors and host species influence these interactions. Through a series of case studies and research findings, the text underscores the ecological importance of AM fungi in sustaining plant health and resilience, with implications for biodiversity conservation and agricultural sustainability. Overall, it serves as a comprehensive resource for understanding the symbiotic relationships that underpin ecosystem functionality and the adaptive strategies of these ancient plant groups.