diff --git a/koans-solved/backquote.lisp b/koans-solved/backquote.lisp
index e1a187d..fef6945 100644
--- a/koans-solved/backquote.lisp
+++ b/koans-solved/backquote.lisp
@@ -26,7 +26,7 @@
     ;; , unquotes a part of the expression.
     (assert-equal '((123) 45 6 z) `(,x 45 6 z))
     (assert-equal '((123) 45 6 (7 8 9)) `(,x 45 6 ,z))
-    ;; ,@ splices an expression into the into the list surrounding it.
+    ;; ,@ splices an expression into the list surrounding it.
     (assert-equal '((123) 45 6 7 8 9) `(,x 45 6 ,@z))
     (assert-equal '(123 45 6 7 8 9) `(,@x 45 6 ,@z))))
 
@@ -34,7 +34,7 @@
   ;; Because of its properties, backquote is useful for constructing Lisp forms
   ;; that are macroexpansions or parts of macroexpansions.
   (let ((variable 'x))
-    ;; Fill in the blank without without using backquote/unquote notation.
+    ;; Fill in the blank without using backquote/unquote notation.
     (assert-equal '(if (typep x 'string)
                     (format nil "The value of ~A is ~A" 'x x)
                     (error 'type-error :datum x :expected-type 'string))
@@ -44,7 +44,7 @@
                                           :expected-type 'string))))
   (let ((error-type 'type-error)
         (error-arguments '(:datum x :expected-type 'string)))
-    ;; Fill in the blank without without using backquote/unquote notation.
+    ;; Fill in the blank without using backquote/unquote notation.
     (assert-equal '(if (typep x 'string)
                     (format nil "The value of ~A is ~A" 'x x)
                     (error 'type-error :datum x :expected-type 'string))
diff --git a/koans-solved/condition-handlers.lisp b/koans-solved/condition-handlers.lisp
index 7d7bee1..36d5ef4 100644
--- a/koans-solved/condition-handlers.lisp
+++ b/koans-solved/condition-handlers.lisp
@@ -186,7 +186,7 @@
     (assert-equal '(:my-error) *list*)))
 
 (define-test handler-case-type
-  ;; A handler cases is not executed if it does not match the condition type.
+  ;; A handler case is not executed if it does not match the condition type.
   (let ((*list* '()))
     (handler-case (signal (make-condition 'error))
       (my-error (condition) (handle-my-error condition))
diff --git a/koans-solved/control-statements.lisp b/koans-solved/control-statements.lisp
index 48b73a1..1fe0acd 100644
--- a/koans-solved/control-statements.lisp
+++ b/koans-solved/control-statements.lisp
@@ -16,7 +16,7 @@
   ;; IF only evaluates and returns one branch of a conditional expression.
   (assert-equal :true (if t :true :false))
   (assert-equal :false (if nil :true :false))
-  ;; This also applies to side effects that migh or might not be evaluated.
+  ;; This also applies to side effects that might or might not be evaluated.
   (let ((result))
     (if t
         (setf result :true)
diff --git a/koans-solved/mapcar-and-reduce.lisp b/koans-solved/mapcar-and-reduce.lisp
index 5774347..d05b542 100644
--- a/koans-solved/mapcar-and-reduce.lisp
+++ b/koans-solved/mapcar-and-reduce.lisp
@@ -16,7 +16,7 @@
 
 (define-test mapcar
   (let ((numbers '(1 2 3 4 5 6)))
-    ;; Inside MAPCAR, he function 1+ will be applied to each element of NUMBERS.
+    ;; Inside MAPCAR, the function 1+ will be applied to each element of NUMBERS.
     ;; A new list will be collected from the results.
     (assert-equal '(2 3 4 5 6 7) (mapcar #'1+ numbers))
     (assert-equal '(-1 -2 -3 -4 -5 -6) (mapcar #'- numbers))
diff --git a/koans-solved/nil-false-empty.lisp b/koans-solved/nil-false-empty.lisp
index ebbd6eb..e832211 100644
--- a/koans-solved/nil-false-empty.lisp
+++ b/koans-solved/nil-false-empty.lisp
@@ -46,7 +46,7 @@
 
 (define-test or
   ;; The logical operator OR can also take multiple arguments.
-  (true-or-false? t  (or nil nil nil t nil))
+  (true-or-false? t (or nil nil nil t nil))
   ;; OR returns the first non-NIL value it encounters, or NIL if there are none.
   (assert-equal nil (or nil nil nil))
   (assert-equal 1 (or 1 2 3 4 5)))
diff --git a/koans/backquote.lisp b/koans/backquote.lisp
index c66deba..1304cae 100644
--- a/koans/backquote.lisp
+++ b/koans/backquote.lisp
@@ -26,7 +26,7 @@
     ;; , unquotes a part of the expression.
     (assert-equal ____ `(,x 45 6 z))
     (assert-equal ____ `(,x 45 6 ,z))
-    ;; ,@ splices an expression into the into the list surrounding it.
+    ;; ,@ splices an expression into the list surrounding it.
     (assert-equal ____ `(,x 45 6 ,@z))
     (assert-equal ____ `(,@x 45 6 ,@z))))
 
@@ -34,7 +34,7 @@
   ;; Because of its properties, backquote is useful for constructing Lisp forms
   ;; that are macroexpansions or parts of macroexpansions.
   (let ((variable 'x))
-    ;; Fill in the blank without without using backquote/unquote notation.
+    ;; Fill in the blank without using backquote/unquote notation.
     (assert-equal ____
                   `(if (typep ,variable 'string)
                        (format nil "The value of ~A is ~A" ',variable ,variable)
@@ -42,7 +42,7 @@
                                           :expected-type 'string))))
   (let ((error-type 'type-error)
         (error-arguments '(:datum x :expected-type 'string)))
-    ;; Fill in the blank without without using backquote/unquote notation.
+    ;; Fill in the blank without using backquote/unquote notation.
     (assert-equal ____
                   `(if (typep x 'string)
                        (format nil "The value of ~A is ~A" 'x x)
diff --git a/koans/condition-handlers.lisp b/koans/condition-handlers.lisp
index c18d1d6..90208a1 100644
--- a/koans/condition-handlers.lisp
+++ b/koans/condition-handlers.lisp
@@ -172,7 +172,7 @@
     (assert-equal ____ *list*)))
 
 (define-test handler-case-type
-  ;; A handler cases is not executed if it does not match the condition type.
+  ;; A handler case is not executed if it does not match the condition type.
   (let ((*list* '()))
     (handler-case (signal (make-condition 'error))
       (my-error (condition) (handle-my-error condition))
diff --git a/koans/control-statements.lisp b/koans/control-statements.lisp
index 13ba43b..93489b1 100644
--- a/koans/control-statements.lisp
+++ b/koans/control-statements.lisp
@@ -16,7 +16,7 @@
   ;; IF only evaluates and returns one branch of a conditional expression.
   (assert-equal ____ (if t :true :false))
   (assert-equal ____ (if nil :true :false))
-  ;; This also applies to side effects that migh or might not be evaluated.
+  ;; This also applies to side effects that might or might not be evaluated.
   (let ((result))
     (if t
         (setf result :true)
diff --git a/koans/mapcar-and-reduce.lisp b/koans/mapcar-and-reduce.lisp
index 76dfa83..2298a2a 100644
--- a/koans/mapcar-and-reduce.lisp
+++ b/koans/mapcar-and-reduce.lisp
@@ -16,7 +16,7 @@
 
 (define-test mapcar
   (let ((numbers '(1 2 3 4 5 6)))
-    ;; Inside MAPCAR, he function 1+ will be applied to each element of NUMBERS.
+    ;; Inside MAPCAR, the function 1+ will be applied to each element of NUMBERS.
     ;; A new list will be collected from the results.
     (assert-equal '(2 3 4 5 6 7) (mapcar #'1+ numbers))
     (assert-equal ____ (mapcar #'- numbers))
diff --git a/koans/nil-false-empty.lisp b/koans/nil-false-empty.lisp
index 6d4dd41..90c2cb7 100644
--- a/koans/nil-false-empty.lisp
+++ b/koans/nil-false-empty.lisp
@@ -46,7 +46,7 @@
 
 (define-test or
   ;; The logical operator OR can also take multiple arguments.
-  (true-or-false? ____  (or nil nil nil t nil))
+  (true-or-false? ____ (or nil nil nil t nil))
   ;; OR returns the first non-NIL value it encounters, or NIL if there are none.
   (assert-equal ____ (or nil nil nil))
   (assert-equal ____ (or 1 2 3 4 5)))