diff --git a/src/Collections/Collection.php b/src/Collections/Collection.php
index cf58f32..208b964 100644
--- a/src/Collections/Collection.php
+++ b/src/Collections/Collection.php
@@ -88,6 +88,27 @@ class Collection extends ImmutableCollection implements ICollection {
         return $this;
     }
 
+    /**
+     * @inheritDoc
+     */
+    public function removeFirst () {
+        $firstKey = $this->firstKey();
+        $firstValue = $this->get($firstKey);
+
+        $this->remove($firstKey);
+        return $firstValue;
+    }
+    /**
+     * @inheritDoc
+     */
+    public function removeLast () {
+        $lastKey = $this->lastKey();
+        $lastValue = $this->get($lastKey);
+
+        $this->remove($lastKey);
+        return $lastValue;
+    }
+
     /**
      * @inheritDoc
      */
@@ -105,6 +126,8 @@ class Collection extends ImmutableCollection implements ICollection {
      * @inheritDoc
      */
     public function sliceSelf (int $offset, ?int $length = null): static {
+        $this->_checkOffset($offset);
+
         $this->elements = array_slice($this->elements, $offset, $length, true);
         return $this;
     }
diff --git a/src/Collections/ICollection.php b/src/Collections/ICollection.php
index d6c6b4c..caf4897 100644
--- a/src/Collections/ICollection.php
+++ b/src/Collections/ICollection.php
@@ -3,6 +3,7 @@
 namespace jrosset\Collections;
 
 use Closure;
+use OutOfBoundsException;
 use Throwable;
 
 /**
@@ -90,6 +91,23 @@ interface ICollection extends IImmutableCollection {
      */
     public function removeValue ($value, bool $strict = false): static;
 
+    /**
+     * Get and remove the first element
+     *
+     * @return TValue The value
+     *
+     * @throws OutOfBoundsException If the collection is empty
+     */
+    public function removeFirst ();
+    /**
+     * Get and remove the last element
+     *
+     * @return TValue The value
+     *
+     * @throws OutOfBoundsException If the collection is empty
+     */
+    public function removeLast ();
+
     /**
      * Keep only a slice of the collection
      *
@@ -99,6 +117,8 @@ interface ICollection extends IImmutableCollection {
      * @param int|null $length The maximum length. Null if until end of the collection
      *
      * @return $this
+     *
+     * @throws OutOfBoundsException If the offset is not valid
      */
     public function sliceSelf (int $offset, ?int $length = null): static;
 
diff --git a/src/Collections/IImmutableCollection.php b/src/Collections/IImmutableCollection.php
index 7867f67..f495caa 100644
--- a/src/Collections/IImmutableCollection.php
+++ b/src/Collections/IImmutableCollection.php
@@ -7,6 +7,7 @@ use Closure;
 use Countable;
 use IteratorAggregate;
 use JsonSerializable;
+use OutOfBoundsException;
 use Throwable;
 
 /**
@@ -52,7 +53,18 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Coun
      *
      * @return TValue|null The value
      */
-    public function get ($key): mixed;
+    public function get ($key);
+    /**
+     * Get the value at an offset
+     *
+     * @param int $offset The offset
+     *
+     * @return TValue The value
+     *
+     * @throws OutOfBoundsException If the offset is not valid
+     */
+    public function getFromOffset (int $offset);
+
     /**
      * Get the first key of a value or null if not found
      *
@@ -62,6 +74,50 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Coun
      * @return TKey|null
      */
     public function key ($value, bool $strict = false);
+    /**
+     * Get the key at an offset
+     *
+     * @param int $offset The offset
+     *
+     * @return TKey The key
+     *
+     * @throws OutOfBoundsException If the offset is not valid
+     */
+    public function keyFromOffset (int $offset);
+
+    /**
+     * Get the value of the first element
+     *
+     * @return TValue The value
+     *
+     * @throws OutOfBoundsException If the collection is empty
+     */
+    public function first ();
+    /**
+     * Get the key of the first element
+     *
+     * @return TKey The key
+     *
+     * @throws OutOfBoundsException If the collection is empty
+     */
+    public function firstKey ();
+
+    /**
+     * Get the value of the last element
+     *
+     * @return TValue The value
+     *
+     * @throws OutOfBoundsException If the collection is empty
+     */
+    public function last ();
+    /**
+     * Get the key of the last element
+     *
+     * @return TKey The key
+     *
+     * @throws OutOfBoundsException If the collection is empty
+     */
+    public function lastKey ();
 
     /**
      * Extract a slice of the collection
@@ -72,6 +128,8 @@ interface IImmutableCollection extends IteratorAggregate, JsonSerializable, Coun
      * @param int|null $length The maximum length. Null if until end of the collection
      *
      * @return static<TKey, TValue> The result collection
+     *
+     * @throws OutOfBoundsException If the offset is not valid
      */
     public function slice (int $offset, ?int $length = null): static;
 
diff --git a/src/Collections/ImmutableCollection.php b/src/Collections/ImmutableCollection.php
index fc8bc1c..fb62bb7 100644
--- a/src/Collections/ImmutableCollection.php
+++ b/src/Collections/ImmutableCollection.php
@@ -5,6 +5,7 @@ namespace jrosset\Collections;
 use ArrayIterator;
 use Closure;
 use InvalidArgumentException;
+use OutOfBoundsException;
 use Traversable;
 
 /**
@@ -124,6 +125,20 @@ class ImmutableCollection implements IImmutableCollection {
     protected function _normalizeKey ($key) {
         return $key;
     }
+    /**
+     * Vérifie un offset (&ge; 0, &lt; {@see static::count()})
+     *
+     * @param int $offset L'offset à vérifier
+     *
+     * @return void
+     *
+     * @throws OutOfBoundsException Si l'offset est invalide
+     */
+    protected function _checkOffset (int $offset): void {
+        if ($offset < 0 || $offset >= $this->count()) {
+            throw new OutOfBoundsException('The offset must be between 0 and ' . ($this->count() - 1));
+        }
+    }
 
     /**
      * @inheritDoc
@@ -217,6 +232,14 @@ class ImmutableCollection implements IImmutableCollection {
     public function get ($key): mixed {
         return $this->elements[$this->_normalizeKey($key)] ?? null;
     }
+    /**
+     * @inheritDoc
+     */
+    public function getFromOffset (int $offset) {
+        $this->_checkOffset($offset);
+        return array_values($this->elements)[$offset];
+    }
+
     /**
      * @inheritDoc
      */
@@ -228,11 +251,46 @@ class ImmutableCollection implements IImmutableCollection {
         }
         return null;
     }
+    /**
+     * @inheritDoc
+     */
+    public function keyFromOffset (int $offset) {
+        $this->_checkOffset($offset);
+        return array_keys($this->elements)[$offset];
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function first () {
+        return $this->getFromOffset(0);
+    }
+    /**
+     * @inheritDoc
+     */
+    public function firstKey () {
+        return $this->keyFromOffset(0);
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function last () {
+        return $this->getFromOffset($this->count() - 1);
+    }
+    /**
+     * @inheritDoc
+     */
+    public function lastKey () {
+        return $this->keyFromOffset($this->count() - 1);
+    }
 
     /**
      * @inheritDoc
      */
     public function slice (int $offset, ?int $length = null): static {
+        $this->_checkOffset($offset);
+
         $output = new static();
 
         $currentIndex = 0;