Mango (Mangifera indica L.) is one of the oldest and choicest tropical fruits of the world and is rightly designated as "King of fruits" in the tropical world. Mango is one of the most profitable crops in tropical and subtropical regions in the world. Because of it's naturally built in qualities, mango is now gradually gaining global market. India is the largest mango producer and consumer. Mango is the leading fruit crop of Gujarat and Saurashtra region. Major mango growing pockets are Valsad and in Saurashtra are Talala (Gir) and Vanthali of Junagadh district, Dhari of Amreli district and Mahuva of Bhavanagar district. Important variety of this region is Kesar, Alphonso and Rajapuri. The changed climatic conditions might play an important role in this fluctuating productivity. GDD are very important in horticulture because it is useful for decide optimum sowing time of plants and fruit maturity. This book is providing guideline to amateur gardeners, researchers', students, policy makers and traders regarding fruit maturity and its forecasting.