I am very confused by the treatment of Peskin on representations of Lorentz group and spinors. I am confronted with this stuff for the first time by the way. For now I just want to start by asking: If, as usual Lorentz transformations rotate and boost frames of reference in Minkowski space, are we considering now rotations and boosts in spin space? And does anybody know about some clear treatments on spinors and representations of the Lorentz group? Any help would be greatly appreciated!!