diff --git a/src/blackmisc/collection.h b/src/blackmisc/collection.h
index 7a7393e8d..e9c334366 100644
--- a/src/blackmisc/collection.h
+++ b/src/blackmisc/collection.h
@@ -188,6 +188,19 @@ namespace BlackMisc
          */
         iterator insert(T &&value) { Q_ASSERT(pimpl()); return pimpl()->insert(std::move(value)); }
 
+        /*!
+         * \brief Inserts all elements from another collection into this collection.
+         * \pre This collection must be initialized.
+         */
+        void insert(const CCollection &other) { std::copy(other.begin(), other.end(), std::inserter(*this, begin())); }
+
+        /*!
+         * \brief Inserts all elements from another collection into this collection.
+         * This version moves elements instead of copying.
+         * \pre This collection must be initialized.
+         */
+        void insert(CCollection &&other) { std::move(other.begin(), other.end(), std::inserter(*this, begin())); }
+
         /*!
          * \brief Synonym for insert.
          * \return An iterator to the position where value was inserted.
@@ -202,6 +215,48 @@ namespace BlackMisc
          */
         iterator push_back(T &&value) { return insert(std::move(value)); }
 
+        /*!
+         * \brief Synonym for insert.
+         * \pre This collection must be initialized.
+         */
+        void push_back(const CCollection &other) { insert(other); }
+
+        /*!
+         * \brief Synonym for insert.
+         * \pre This collection must be initialized.
+         */
+        void push_back(CCollection &&other) { insert(std::move(other)); }
+
+        /*!
+         * \brief Returns a collection which is the union of this collection and another.
+         */
+        CCollection makeUnion(const CCollection &other) const
+        {
+            CCollection result;
+            std::set_union(begin(), end(), other.begin(), other.end(), std::inserter(result, result.begin()));
+            return result;
+        }
+
+        /*!
+         * \brief Returns a collection which is the intersection of this collection and another.
+         */
+        CCollection intersection(const CCollection &other) const
+        {
+            CCollection result;
+            std::set_intersection(begin(), end(), other.begin(), other.end(), std::inserter(result, result.begin()));
+            return result;
+        }
+
+        /*!
+         * \brief Returns a collection which contains all the elements from this collection which are not in the other collection.
+         */
+        CCollection difference(const CCollection &other) const
+        {
+            CCollection result;
+            std::set_difference(begin(), end(), other.begin(), other.end(), std::inserter(result, result.begin()));
+            return result;
+        }
+
         /*!
          * \brief Remove the element pointed to by the given iterator.
          * \return An iterator to the position of the next element after the one removed.
@@ -237,6 +292,12 @@ namespace BlackMisc
          */
         void remove(const T &object) { auto it = find(object); if (it != end()) { erase(it); } }
 
+        /*!
+         * \brief Removes from this collection all of the elements of another collection.
+         * \pre This sequence must be initialized.
+         */
+        void remove(const CCollection &other) { *this = CCollection(*this).difference(other); }
+
         /*!
          * \brief Test for equality.
          * \todo Improve inefficient implementation.
diff --git a/src/blackmisc/sequence.h b/src/blackmisc/sequence.h
index 2ef33c65d..9a98e7d98 100644
--- a/src/blackmisc/sequence.h
+++ b/src/blackmisc/sequence.h
@@ -206,6 +206,19 @@ namespace BlackMisc
          */
         void push_back(T &&value) { Q_ASSERT(pimpl()); pimpl()->push_back(std::move(value)); }
 
+        /*!
+         * \brief Appends all elements from another sequence at the end of this sequence.
+         * \pre This sequence must be initialized.
+         */
+        void push_back(const CSequence &other) { std::copy(other.begin(), other.end(), std::back_inserter(*this)); }
+
+        /*!
+         * \brief Appends all elements from another sequence at the end of this sequence.
+         * This version moves elements instead of copying.
+         * \pre This sequence must be initialized.
+         */
+        void push_back(CSequence &&other) { std::move(other.begin(), other.end(), std::back_inserter(*this)); }
+
         /*!
          * \brief Synonym for push_back.
          * \pre The sequence must be initialized.
@@ -218,6 +231,24 @@ namespace BlackMisc
          */
         void insert(T &&value) { push_back(std::move(value)); }
 
+        /*!
+         * \brief Synonym for push_back.
+         * \pre The sequence must be initialized.
+         */
+        void insert(const CSequence &other) { push_back(other); }
+
+        /*!
+         * \brief Synonym for push_back.
+         * \pre The sequence must be initialized.
+         */
+        void insert(CSequence &&other) { push_back(std::move(other)); }
+
+        /*!
+         * \brief Concatenates two sequences and returns the result.
+         * \pre This sequence must be initialized.
+         */
+        CSequence join(const CSequence &other) const { CSequence copy(*this); copy.push_back(other); return copy; }
+
         /*!
          * \brief Removes an element at the end of the sequence.
          * \pre The sequence must contain at least one element.
diff --git a/tests/blackmisc/testcontainers.cpp b/tests/blackmisc/testcontainers.cpp
index 9f1e97e44..8d2bad3c9 100644
--- a/tests/blackmisc/testcontainers.cpp
+++ b/tests/blackmisc/testcontainers.cpp
@@ -67,4 +67,46 @@ namespace BlackMiscTest
         QVERIFY2(s1.back() == 1, "Last element has expected value");
     }
 
+    void CTestContainers::joinAndSplit()
+    {
+        CSequence<int> s1, s2;
+        s1.push_back(1);
+        s1.push_back(2);
+        s1.push_back(3);
+        s2.push_back(4);
+        s2.push_back(5);
+        s2.push_back(6);
+        auto joined = s1.join(s2);
+        s1.push_back(s2);
+        QVERIFY2(s1.size() == 6, "Combine sequences");
+        QVERIFY2(s1 == joined, "Combine sequences");
+
+        CCollection<int> c1, c2, c3, c4;
+        c1.push_back(1);
+        c1.push_back(2);
+        c1.push_back(3);
+        c1.push_back(4);
+        c1.push_back(5);
+        c1.push_back(6);
+        c2.push_back(1);
+        c2.push_back(2);
+        c2.push_back(3);
+        c3.push_back(4);
+        c3.push_back(5);
+        c3.push_back(6);
+        c4.push_back(10);
+        c4.push_back(20);
+        c4.push_back(30);
+        QVERIFY2(c1.makeUnion(c2) == c1, "Combine collections");
+        QVERIFY2(c2.makeUnion(c3) == c1, "Combine collections");
+        QVERIFY2(c1.intersection(c2) == c2, "Combine collections");
+        QVERIFY2(c1.difference(c2) == c3, "Split collections");
+        c1.insert(c4);
+        QVERIFY2(c1.size() == 9, "Combine collections");
+        c1.remove(c4);
+        QVERIFY2(c1.size() == 6, "Split collections");
+        c1.remove(c2);
+        QVERIFY2(c1 == c3, "Split collections");
+    }
+
 } //namespace BlackMiscTest
\ No newline at end of file
diff --git a/tests/blackmisc/testcontainers.h b/tests/blackmisc/testcontainers.h
index 39686a0c2..b9c5a6730 100644
--- a/tests/blackmisc/testcontainers.h
+++ b/tests/blackmisc/testcontainers.h
@@ -21,6 +21,7 @@ namespace BlackMiscTest
     private slots:
         void collectionBasics();
         void sequenceBasics();
+        void joinAndSplit();
     };
 
 } //namespace BlackMiscTest