Take[list, n] gives the first n elements of list.
Take[list, -n] gives the last n elements of list.
Take[list, m, n] gives elements m through n of list.
Take[list, m, n, s] gives elements m through n in steps of s.
Take[list, , , ... ] gives a nested list in which elements specified by are taken at level i in list.
Take uses the standard sequence specification (see Section A.3.5).
Examples: Take[a,b,c,d,e, 3] .
Take[a,b,c,d,e, -2] .
Take[Range, 3, 12, 4] .
Take can be used on an object with any head, not necessarily List.
Take[list, , ] effectively extracts a submatrix from list.
Example: Take[a,b,c,d,e,f, -1, 2] .
See The Mathematica Book: Section 1.8.4.
See also: Part, Drop, StringTake, Select, Cases, Partition, PadLeft.
Related package: LinearAlgebra`MatrixManipulation`.