The materials here have been developed to support students or as supplementary material to my published books. Once again, the site is going through a redesign, which will involve moving over the old study materials and revising them. Whilst I do this, some material will be available in the old format, whilst other bits will be unavailable so as to avoid glitches. I will rerelease material bit by bit, as sections are complete. Apologies in advance for any inconvenience caused.