Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Programming the Z80 is a seminal computer programming text, written by Rodnay Zaks and first published in 1979 by Sybex. It is designed as both an educational text to teach programming techniques of elementary to intermediate level using assembly language, and as a self-contained reference book. It covers more general concepts, such as information representation and data structures, and describes in detail topics specific to the Zilog Z80 microprocessor, such as its internal hardware organisation and instruction set. The book is considered an indispensable reference guide by many Z80 programmers. It was also published by RadioShack with the title How To Program The Z80. In 1983, Sybex published a companion volume, Z80 Applications written by James W. Coffron.
