diff --git a/book/src/language-tour/assert.md b/book/src/language-tour/assert.md
index 878a2425..72e71fc2 100644
--- a/book/src/language-tour/assert.md
+++ b/book/src/language-tour/assert.md
@@ -1,7 +1,7 @@
 # Assert
 
-```
-assert rawdata is SomeType
+```gleam
+assert rawdata = SomeType
 ```
 
 Causes the script to fail if the rawdata doesn't match the structure of datumtype
diff --git a/book/src/language-tour/blocks.md b/book/src/language-tour/blocks.md
index ec5b7c02..6bfe0563 100644
--- a/book/src/language-tour/blocks.md
+++ b/book/src/language-tour/blocks.md
@@ -2,7 +2,7 @@
 
 If statements
 
-```
+```gleam
 if condition {
 
 } else {
@@ -12,7 +12,7 @@ if condition {
 
 Case Patterns
 
-```
+```gleam
 when color is {
     Green -> "Success."
     Blue -> "Warning."
@@ -22,7 +22,7 @@ when color is {
 
 Let bindings with blocks
 
-```
+```gleam
 let num = -5
 let absNum = if num>=0 {num} else {-num}
 
diff --git a/book/src/language-tour/bool.md b/book/src/language-tour/bool.md
index bd2476fc..5a3e892a 100644
--- a/book/src/language-tour/bool.md
+++ b/book/src/language-tour/bool.md
@@ -1,3 +1,19 @@
 # Bool
 
-Bools are True or False
\ No newline at end of file
+Bools are True or False
+
+There are logical conjunctions (True && True) or disjunctions (True || False).
+
+```gleam
+fn negate(b: Bool)->Bool {
+    if b {
+        False
+    }else{
+        True
+    }
+}
+
+fn and(b: Bool, c: Bool, d: Bool)->Bool{
+    b && c && d
+}
+```
\ No newline at end of file
diff --git a/book/src/language-tour/comments.md b/book/src/language-tour/comments.md
index 131c7084..3d9627da 100644
--- a/book/src/language-tour/comments.md
+++ b/book/src/language-tour/comments.md
@@ -1,6 +1,6 @@
 # Comments
 
-```
+```gleam
 // Line comments begin with a double-slash
 
 /// Doc comments begin with a triple-slash
diff --git a/book/src/language-tour/constants.md b/book/src/language-tour/constants.md
index 21fb31ed..f3ef62ca 100644
--- a/book/src/language-tour/constants.md
+++ b/book/src/language-tour/constants.md
@@ -1 +1,8 @@
 # Constants
+
+Constants (not implemented yet) will be set in the global scope like so:
+```gleam
+const x = 1
+```
+
+Similar to a let binding, but with a const keyword instead.
\ No newline at end of file
diff --git a/book/src/language-tour/custom-types.md b/book/src/language-tour/custom-types.md
index 19c002d1..59df99f9 100644
--- a/book/src/language-tour/custom-types.md
+++ b/book/src/language-tour/custom-types.md
@@ -5,7 +5,7 @@
 
 Instantiation
 
-```
+```gleam
 type Color {
     Red
     Blue
@@ -18,7 +18,7 @@ Enum types can be thought of as the unit of product types.
 
 Usage
 
-```
+```gleam
 fn myFavouriteColor() -> Color {
     Red
 }
@@ -26,14 +26,14 @@ fn myFavouriteColor() -> Color {
 
 ### Product Types
 
-```
+```gleam
 type MyValue {
     Name(String)
     Age(Int)
 }
 ```
 
-```
+```gleam
 fn eitherNameOrAge(b: Bool) -> MyValue {
     if b {
         Name("James")
diff --git a/book/src/language-tour/functions.md b/book/src/language-tour/functions.md
index 0c5faf50..bcdb0d16 100644
--- a/book/src/language-tour/functions.md
+++ b/book/src/language-tour/functions.md
@@ -1 +1,43 @@
 # Functions
+
+Functions can be instantiated like so:
+```gleam
+fn f(x) {
+
+}
+```
+l functions in aiken are pure without side effect, so all functions also must return some value.
+A function with no return value (like above) will error.
+
+Providing arg types:
+```gleam
+fn f(x: Int) {
+
+}
+```
+
+and return types:
+
+```gleam
+fn f(x: Int) -> Int {
+
+}
+```
+
+and the last value is implicitly returned:
+
+```gleam
+fn f(x: Int) -> Int {
+    x + 1
+}
+```
+
+Functions can be made public in modules so they can be accessed by others
+
+```gleam
+pub fn myFunction(a: List(a)) {
+    // do something useful...
+}
+```
+
+A
\ No newline at end of file
diff --git a/book/src/language-tour/int.md b/book/src/language-tour/int.md
index 18f49fe7..130de243 100644
--- a/book/src/language-tour/int.md
+++ b/book/src/language-tour/int.md
@@ -1 +1,15 @@
 # Int
+
+Ints are plutus integers which are arbitrary size.
+
+So, there is no underflow. Basic arithmetic can be done for O(1) between ints (+,-,*).
+
+```gleam
+// A convenient helper function to get the number 7.
+pub fn get7(){
+    let x = 3
+    let y = 2
+    let z = 1
+    x*y + z
+}
+```
\ No newline at end of file
diff --git a/book/src/language-tour/list.md b/book/src/language-tour/list.md
index 6811f7b8..32656cf4 100644
--- a/book/src/language-tour/list.md
+++ b/book/src/language-tour/list.md
@@ -1 +1,21 @@
 # List
+
+Aiken lists are plutus linked lists. Accessing by index is O(n). Appending or accessing head is O(1). Grabbing tail is O(1).
+
+There is no builtin syntax for accessing by index as this is implemented by standard libs.
+
+Accessing head, tail, or preceding elements can be done by pattern matching.
+
+```gleam
+// this function checks if a list has a sequence of 1 then 2 contained within it.
+fn listStuff(a: List(Int)){
+    when a is {
+        [1,2, ..tail] -> True
+        []->False
+        _ -> listStuff([2, ..tail])
+    }
+}
+```
+
+Helper functions for safely accessing head, tail, are provided in standard lib but are implemented using comprehensions.
+It is usually best to use your own comprehensions for efficiency (until the optimiser is better).
\ No newline at end of file
diff --git a/book/src/language-tour/option.md b/book/src/language-tour/option.md
index f33af4ff..a1fae1da 100644
--- a/book/src/language-tour/option.md
+++ b/book/src/language-tour/option.md
@@ -1 +1,23 @@
 # Option
+
+We define option as a generic type like so
+
+```
+pub type Option(a) {
+    None
+    Some(a)
+}
+```
+
+Then, functions which fail may safely return an optional value.
+
+```
+pub fn getHead(a: List(a))->a {
+    when a is {
+        [a, .._]->Some(a)
+        []->None
+    }
+}
+```
+
+An unsafe variant of this function might instead assert that there is a head, and return it.