This document discusses deep foundation and pile foundations. It begins with an introduction to deep foundations, which provide support below a structure through end bearing and/or skin friction. Pile foundations are then introduced as a type of deep foundation that transfers loads through vertical members driven or cast into the ground. The document proceeds to classify and describe pile foundations based on construction method, material, function, shape and size. It also discusses uses of pile foundations and methods of pile installation, particularly the use of pile hammers to drive displacement piles into the ground.