diff --git a/sortedmap.c b/sortedmap.c
index 415e317..448b809 100644
--- a/sortedmap.c
+++ b/sortedmap.c
@@ -47,9 +47,9 @@ SortedMap * put_map(SortedMap *this, char *key, void *value) {
 		leaf->content.value = value;
 		intern = malloc(sizeof(SortedMap));
 		intern->type = INTERN;
-		intern->key = this->key;
-		intern->content.children.l = cmp < 0 ? leaf : this;
-		intern->content.children.r = cmp < 0 ? this : leaf;
+		intern->key = cmp <= 0 ? key : this->key;
+		intern->content.children.l = cmp <= 0 ? leaf : this;
+		intern->content.children.r = cmp <= 0 ? this : leaf;
 		return intern;
 	case INTERN:
 		if (cmp <= 0) {
diff --git a/sortedmap.h b/sortedmap.h
index 9bab76e..7482f5e 100644
--- a/sortedmap.h
+++ b/sortedmap.h
@@ -1,5 +1,9 @@
 #ifndef SORTED_MAP
 #define SORTED_MAP
+/* A map datastructure which maps strings to void*.
+ * A binary search tree putting string equal to or smaller than the current node left.
+ */
+
 enum nodetype { EMPTY, LEAF, INTERN };
 
 typedef struct node {