Added "and" and "or" to the early part of the ink doc

Documentation/WritingWithInk.md

@@ -541,7 +541,15 @@ You can use several logical tests on an option; if you do, *all* the tests must
 	+ 	{ visit_paris } { not bored_of_paris } 
 		[Return to Paris] -> visit_paris 
 
+#### Logical operators: AND and OR 
 
+The above "multiple conditions" are really just conditions with an the usual programming AND operator. Ink supports `and` (also written as `&&`) and `or` (also written as `||`) in the usual way, as well as brackets. 
+
+	*	{ not (visit_paris or visit_rome) && (visit_london || visit_new_york) } [ Wait. Go where? I'm confused. ] -> visit_someplace
+
+For non-programmers `X and Y` means both X and Y must be true. `X or Y` means either or both. We don't have a `xor`. 
+
+You can also use the standard `!` for `not`, though it'll sometimes confuse the compiler which thinks `{!text}` is a once-only list. We recommend using `not` because negated boolean tests are never that exciting. 
 
 #### Advanced: knot/stitch labels are actually read counts
 
@@ -555,6 +563,7 @@ If it's non-zero, it'll return true in a test like the one above, but you can al
 
 	* {seen_clue > 3} [Flat-out arrest Mr Jefferson]
 
+
 #### Advanced: more logic
 
 **ink** supports a lot more logic and conditionality than covered here - see the section on 'variables and logic'.