This document discusses various trading strategies using portfolios of options, including bull spreads, bear spreads, butterfly spreads, calendar spreads, and combinations of calls and puts. Bull spreads involve buying a lower strike call and writing a higher strike call, or buying a lower strike put and writing a higher strike put. Bear spreads are the opposite. Butterfly spreads involve positions in options with three different strike prices. Calendar spreads have positions in options with the same strike but different expiration dates. Combination strategies include straddles, strangles, strips, and straps that combine both puts and calls.