### Clue: Pictures in one book of maps taken from periodicals (8)
### Answer: IMAGINES 
 ### Explanation: Definition: Pictures
 I(Roman numeral for "one") + "A-Z"(a book of maps;an atlas of street maps, the first of which to be published was for London) **deleted from**(taken from) "magazines"(periodicals).
Defn: … in one's mind.