  This paper presents, with explanatory details, the handle decompositions,
fundamental groups and homology groups of 3-manifolds, including some knot
complements. Hence, along this paper, when the word manifold appears it is
implicit that its dimension is 3, except when explicitly generalized for n
dimensions, n natural. The results were obtained for: 3-torus, projective space
P^3, trefoil (3^1), figure-eight (4^1), cinquefoil (5^1) and three-twist (5^2).
