(Last name, Year)
Last name, First name and Last name, First name (Year). Title. X. ed. Place of publication: Publisher. URL [Accessed: date].
It is very uncommon to cite an edited book in its entirety. Usually you should cite the part of the book you have used - such as a chapter - and credit the author of that chapter. To do this you can follow the instructions for citing Book chapters.
However, in some special cases it might be relevant to cite an edited book as a whole. You can then follow the instructions below.
(Last name, Year)
Last name, First name and Last name, First name ed(s). (Year). Title. X. ed. Place of publication: Publisher. URL [Accessed: date].