People who only have a general interest in Spectrums reading this site will probably not be interested in the new article over on the Z80 Support Page - it's all about the low-level side of Z80 interrupts. The article details the behaviour of the Z80 CPU with regards the interrupt timing - what actually happens within the processor when an interrupt occurs, the fact that the interrupt could be up to 23 ticks late, and so on. It's quite technical stuff, but should be useful for anyone coding in Z80 (for Spectrums or otherwise), or those writing emulators. Have a read. Be enlightened.