The document discusses different types of organs used in 1960s rock music, including the cheaper and more portable Vox/Farfisa organs and the Hammond organ. It describes the Hammond's tonal qualities like its tone bar faders and percussion options. It highlights famous Hammond players like Jimmy Smith who fully exploited the instrument's abilities, and Booker T and Jon Lord who created iconic Hammond riffs and helped popularize plugging it into guitar amplifiers. The document also gives examples of Hammond playing styles like sustaining chords, using single sustained notes, and "stab" chord accents.