RNA or ribonucleic acid is a molecule essential for coding, decoding, regulation, and expression of genes. It is single-stranded and composed of ribose sugar, phosphate, and nitrogenous bases. It transmits genetic information from DNA to ribosomes for protein synthesis. RNAs play crucial roles in the biological processes of plants, extending beyond their classical function in protein synthesis. Messenger RNA (mRNA) conveys genetic information from DNA to ribosomes, facilitating protein production essential for plant growth and development. Ribosomal RNA (rRNA) forms the core of ribosome's structure and function. Transfer RNA (tRNA) is pivotal in translating mRNA into amino acid sequences. Small RNAs, including microRNAs (miRNAs) and small interfering RNAs (siRNAs), regulate gene expression at the post-transcriptional level, influencing plant development, stress responses, and pathogen defense. Long non-coding RNAs (lncRNAs) are involved in chromatin remodeling, transcriptional regulation, and response to environmental stimuli. Additionally, circular RNAs (circRNAs) act as gene expression regulators and are implicated in plant stress tolerance. Collectively, these various RNA molecules ensure plants adapt and thrive by managing gene expression, responding to environmental changes, and maintaining cellular homeostasis. The topics included in this book on RNA are of utmost significance and bound to provide incredible insights to readers. There has been rapid progress in this field and its applications are finding their way across multiple industries. This book aims to equip students and experts with the advanced topics and upcoming concepts in this area.