This document discusses different types of foundations, focusing on pile foundations. It defines foundations and classifies them as either shallow or deep. Pile foundations are described as deep foundations that transfer loads to deeper, stronger soils using piles. The main types of piles - displacement, replacement, and installation techniques - are outlined. Specific pile types are then detailed, including pre-cast concrete, pre-stressed concrete spun, steel H, bored, and wood piles. The document concludes by describing end bearing piles, friction piles, settlement reducing piles, and piles in fill.