This book contains select proceedings of the 10th annual conference of Deep Foundations Institute of India, DFI India, 2021.  It presents papers on 1) Geotechnical Investigation, Testing, Instrumentation, Monitoring, and Quality Management, 2) Ground Improvement Techniques, 3) Piling and Deep Foundation Techniques, 4) Earth Retention and Deep Excavation Support, 5) Research, Experimental and Numerical Methods in Deep Foundations and Deep Excavation Technologies, and 6) Safe and Efficient Geo-Construction. This book has seventeen articles, each with a specific field application value. The probabilistic approach in evaluating the field data, namely SPT N and pressure meter modulus for arriving at the geotechnical design parameters, multiphase site investigation program for complex underground construction activity, the safety of working platforms in foundation construction projects, usage of liner piles to support the reaction platform for static loading tests for piles, choice of foundation system for three bridges, emphasis on the importance of selecting an appropriate foundation system for the safe and timely completion of the project, challenges in deep excavations, constructions in confined spaces, groundwater level variations, and their influence on tunneling have been discussed. The usefulness of numerical analysis in the design of deep excavations and ground improvement projects is highlighted. The articles covered in this book are of immense value to professionals and academicians for improving their work practice.