diff --git a/QWERTYkez.ExcelProcessor/Editors/ExcelSheet.cs b/QWERTYkez.ExcelProcessor/Editors/ExcelSheet.cs
index d4cdcad..8e4cd11 100644
--- a/QWERTYkez.ExcelProcessor/Editors/ExcelSheet.cs
+++ b/QWERTYkez.ExcelProcessor/Editors/ExcelSheet.cs
@@ -212,20 +212,63 @@ internal sealed class ExcelSheet : ISheet
     /// <inheritdoc />
     public IRange RangeByIndexes(uint startRow, uint startCol, uint endRow, uint endCol)
     {
-        return new ExcelRange(Book, this, startRow, startCol, endRow, endCol);
+        if (startRow == 0) throw new ArgumentException("startRow must be >= 1", nameof(startRow));
+        if (startCol == 0) throw new ArgumentException("startCol must be >= 1", nameof(startCol));
+        if (endRow == 0) throw new ArgumentException("endRow must be >= 1", nameof(endRow));
+        if (endCol == 0) throw new ArgumentException("endCol must be >= 1", nameof(endCol));
+
+        // Приводим к корректному порядку (пользователь мог передать start > end)
+        uint rowStart = Math.Min(startRow, endRow);
+        uint rowEnd = Math.Max(startRow, endRow);
+        uint colStart = Math.Min(startCol, endCol);
+        uint colEnd = Math.Max(startCol, endCol);
+
+        return new ExcelRange(Book, this, rowStart, colStart, rowEnd, colEnd);
     }
 
     /// <inheritdoc />
     public IRange RangeByIndexes(uint startRow, string startCol, uint endRow, string endCol)
     {
+        if (string.IsNullOrEmpty(startCol)) throw new ArgumentException("startCol cannot be null or empty", nameof(startCol));
+        if (string.IsNullOrEmpty(endCol)) throw new ArgumentException("endCol cannot be null or empty", nameof(endCol));
+
         uint startColIdx = CellAddressHelper.ColumnLetterToIndex(startCol);
         uint endColIdx = CellAddressHelper.ColumnLetterToIndex(endCol);
-        return new ExcelRange(Book, this, startRow, startColIdx, endRow, endColIdx);
+        if (startColIdx == 0) throw new ArgumentException($"Invalid column letter: '{startCol}'", nameof(startCol));
+        if (endColIdx == 0) throw new ArgumentException($"Invalid column letter: '{endCol}'", nameof(endCol));
+
+        return RangeByIndexes(startRow, startColIdx, endRow, endColIdx);
+    }
+
+    /// <inheritdoc />
+    public IRange RangeByLength(uint startRow, uint startCol, uint rows, uint cols)
+    {
+        if (startRow == 0) throw new ArgumentException("startRow must be >= 1", nameof(startRow));
+        if (startCol == 0) throw new ArgumentException("startCol must be >= 1", nameof(startCol));
+        if (rows == 0) throw new ArgumentException("rows must be > 0", nameof(rows));
+        if (cols == 0) throw new ArgumentException("cols must be > 0", nameof(cols));
+
+        checked
+        {
+            uint endRow = startRow + rows - 1;
+            uint endCol = startCol + cols - 1;
+            return new ExcelRange(Book, this, startRow, startCol, endRow, endCol);
+        }
+    }
+
+    /// <inheritdoc />
+    public IRange RangeByLength(uint startRow, string startCol, uint rows, uint cols)
+    {
+        if (string.IsNullOrEmpty(startCol)) throw new ArgumentException("startCol cannot be null or empty", nameof(startCol));
+        uint startColIdx = CellAddressHelper.ColumnLetterToIndex(startCol);
+        if (startColIdx == 0) throw new ArgumentException($"Invalid column letter: '{startCol}'", nameof(startCol));
+        return RangeByLength(startRow, startColIdx, rows, cols);
     }
 
     /// <inheritdoc />
     public ISheet RangeByIndexes(uint startRow, uint startCol, uint endRow, uint endCol, Action<IRange> edit)
     {
+        if (edit is null) throw new ArgumentNullException(nameof(edit));
         var range = RangeByIndexes(startRow, startCol, endRow, endCol);
         edit(range);
         return this;
@@ -234,31 +277,16 @@ internal sealed class ExcelSheet : ISheet
     /// <inheritdoc />
     public ISheet RangeByIndexes(uint startRow, string startCol, uint endRow, string endCol, Action<IRange> edit)
     {
+        if (edit is null) throw new ArgumentNullException(nameof(edit));
         var range = RangeByIndexes(startRow, startCol, endRow, endCol);
         edit(range);
         return this;
     }
 
-    /// <inheritdoc />
-    public IRange RangeByLength(uint startRow, uint startCol, uint rows, uint cols)
-    {
-        if (rows == 0 || cols == 0)
-            throw new ArgumentException("Rows and columns must be greater than 0");
-        uint endRow = startRow + rows - 1;
-        uint endCol = startCol + cols - 1;
-        return new ExcelRange(Book, this, startRow, startCol, endRow, endCol);
-    }
-
-    /// <inheritdoc />
-    public IRange RangeByLength(uint startRow, string startCol, uint rows, uint cols)
-    {
-        uint startColIdx = CellAddressHelper.ColumnLetterToIndex(startCol);
-        return RangeByLength(startRow, startColIdx, rows, cols);
-    }
-
     /// <inheritdoc />
     public ISheet RangeByLength(uint startRow, uint startCol, uint rows, uint cols, Action<IRange> edit)
     {
+        if (edit is null) throw new ArgumentNullException(nameof(edit));
         var range = RangeByLength(startRow, startCol, rows, cols);
         edit(range);
         return this;
@@ -267,6 +295,7 @@ internal sealed class ExcelSheet : ISheet
     /// <inheritdoc />
     public ISheet RangeByLength(uint startRow, string startCol, uint rows, uint cols, Action<IRange> edit)
     {
+        if (edit is null) throw new ArgumentNullException(nameof(edit));
         var range = RangeByLength(startRow, startCol, rows, cols);
         edit(range);
         return this;
@@ -274,4 +303,27 @@ internal sealed class ExcelSheet : ISheet
 
     #endregion
 
+
+
+
+    #region Merge Operations
+
+    /// <inheritdoc />
+    public bool TryMergeByIndexes(uint startRow, uint startCol, uint endRow, uint endCol) =>
+        RangeByIndexes(startRow, startCol, endRow, endCol).TryMerge();
+
+    /// <inheritdoc />
+    public bool TryMergeByIndexes(uint startRow, string startCol, uint endRow, string endCol) =>
+        RangeByIndexes(startRow, startCol, endRow, endCol).TryMerge();
+
+    /// <inheritdoc />
+    public bool TryMergeByLength(uint startRow, uint startCol, uint rows, uint cols) =>
+        RangeByLength(startRow, startCol, rows, cols).TryMerge();
+
+    /// <inheritdoc />
+    public bool TryMergeByLength(uint startRow, string startCol, uint rows, uint cols) =>
+        RangeByLength(startRow, startCol, rows, cols).TryMerge();
+
+    #endregion
+
 }
\ No newline at end of file
diff --git a/QWERTYkez.ExcelProcessor/Editors/Interfaces.cs b/QWERTYkez.ExcelProcessor/Editors/Interfaces.cs
index 7d0abd0..4c403cd 100644
--- a/QWERTYkez.ExcelProcessor/Editors/Interfaces.cs
+++ b/QWERTYkez.ExcelProcessor/Editors/Interfaces.cs
@@ -99,6 +99,18 @@ public interface ISheet
     /// <summary>Редактирует диапазон, заданный начальной ячейкой и размером (буква столбца).</summary>
     ISheet RangeByLength(uint startRow, string startCol, uint rows, uint cols, Action<IRange> edit);
 
+    /// <summary>Возвращает диапазон ячеек по начальным и конечным индексам строк и столбцов.</summary>
+    bool TryMergeByIndexes(uint startRow, uint startCol, uint endRow, uint endCol);
+
+    /// <summary>Возвращает диапазон ячеек по начальным и конечным координатам с буквенным обозначением столбцов.</summary>
+    bool TryMergeByIndexes(uint startRow, string startCol, uint endRow, string endCol);
+
+    /// <summary>Возвращает диапазон, начиная с указанной ячейки, заданной размером (строки x столбцы).</summary>
+    bool TryMergeByLength(uint startRow, uint startCol, uint rows, uint cols);
+
+    /// <summary>Возвращает диапазон по начальной ячейке и размеру с буквенным обозначением столбца.</summary>
+    bool TryMergeByLength(uint startRow, string startCol, uint rows, uint cols);
+
     /// <summary>Возвращает ячейку по номеру строки и столбца (оба начиная с 1).</summary>
     ICell Cell(uint row, uint col);