diff --git a/ng-grid/ng-grid-tests.ts b/ng-grid/ng-grid-tests.ts
index 5f4ab6ce5..53763b1a5 100644
--- a/ng-grid/ng-grid-tests.ts
+++ b/ng-grid/ng-grid-tests.ts
@@ -1,27 +1,27 @@
 /// <reference path="ng-grid.d.ts" />
 
-var options1: ngGrid.GridOptions = {
+var options1: ngGrid.IGridOptions = {
     data: [{ 'Name': 'Bob' }, { 'Name': 'Jane' }]
 };
 
-var options2: ngGrid.GridOptions = {
+var options2: ngGrid.IGridOptions = {
     afterSelectionChange: () => { },
-    beforeSelectionChange: () => { },
+    beforeSelectionChange: () => {return true; },
     dataUpdated: () => { }
 };
 
-var options3: ngGrid.GridOptions = {
+var options3: ngGrid.IGridOptions = {
     columnDefs: [
         { field: 'name', displayName: 'Name' },
         { field: 'age', displayName: 'Age' }
     ]
 };
 
-var options4: ngGrid.GridOptions = {
+var options4: ngGrid.IGridOptions = {
     pagingOptions: {
         pageSizes: [1, 2, 3, 4],
         pageSize: 2,
         totalServerItems: 100,
         currentPage: 1
     }
-};
\ No newline at end of file
+};
diff --git a/ng-grid/ng-grid.d.ts b/ng-grid/ng-grid.d.ts
index 48eec367a..f081b362c 100644
--- a/ng-grid/ng-grid.d.ts
+++ b/ng-grid/ng-grid.d.ts
@@ -11,13 +11,13 @@ declare class ngGridReorderable {
 
 declare module ngGrid {
 
-    export interface GridOptions {
+    export interface IGridOptions {
 
         /** Define an aggregate template to customize the rows when grouped. See github wiki for more details. */
-        aggregateTemplate?: any;
+        aggregateTemplate?: string;
 
         /** Callback for when you want to validate something after selection. */
-        afterSelectionChange?: Function;
+        afterSelectionChange?: (rowItem?: any, event?: any) => void ;
 
         /** Callback if you want to inspect something before selection,
         return false if you want to cancel the selection. return true otherwise. 
@@ -25,16 +25,16 @@ declare module ngGrid {
         use rowItem.changeSelection(event) method after returning false initially. 
         Note: when shift+ Selecting multiple items in the grid this will only get called
         once and the rowItem will be an array of items that are queued to be selected. */
-        beforeSelectionChange?: Function;
+        beforeSelectionChange?: (rowItem?: any, event?: any) => boolean ;
 
         /** checkbox templates. */
-        checkboxCellTemplate?: any;
+        checkboxCellTemplate?: string;
 
         /** checkbox templates. */
-        checkboxHeaderTemplate?: any;
+        checkboxHeaderTemplate?: string;
 
         /** definitions of columns as an array [], if not defined columns are auto-generated. See github wiki for more details. */
-        columnDefs?: ColumnDef[];
+        columnDefs?: IColumnDef[];
 
         /** Data being displayed in the grid. Each item in the array is mapped to a row being displayed. */
         data?: any[];
@@ -79,7 +79,7 @@ declare module ngGrid {
         filterText: The text bound to the built-in search box. 
         useExternalFilter: Bypass internal filtering if you want to roll your own filtering mechanism but want to use builtin search box.
         */
-        filterOptions?: FilterOptions;
+        filterOptions?: IFilterOptions;
 
         /** Defining the height of the footer in pixels. */
         footerRowHeight?: number;
@@ -91,7 +91,7 @@ declare module ngGrid {
         headerRowHeight?: number;
 
         /** Define a header row template for further customization. See github wiki for more details. */
-        headerRowTemplate?: any;
+        headerRowTemplate?: string;
 
         /** Enables the use of jquery UI reaggable/droppable plugin. requires jqueryUI to work if enabled. 
         Useful if you want drag + drop but your users insist on crappy browsers. */
@@ -105,13 +105,13 @@ declare module ngGrid {
 
         /** Maintains the column widths while resizing. 
         Defaults to true when using *'s or undefined widths. Can be ovverriden by setting to false. */
-        maintainColumnRatios?: any;
+        maintainColumnRatios?: boolean;
 
         /** Set this to false if you only want one item selected at a time */
         multiSelect?: boolean;
 
         /**  pagingOptions - */
-        pagingOptions?: PagingOptions;
+        pagingOptions?: IPagingOptions;
 
         /** Array of plugin functions to register in ng-grid */
         pinSelectionCheckbox?: boolean;
@@ -123,7 +123,7 @@ declare module ngGrid {
         rowHeight?: number;
 
         /** Define a row template to customize output. See github wiki for more details. */
-        rowTemplate?: any;
+        rowTemplate?: string;
 
         /** all of the items selected in the grid. In single select mode there will only be one item in the array. */
         selectedItems?: any[];
@@ -170,15 +170,20 @@ declare module ngGrid {
         enableHighlighting?: boolean;
     }
 
-    export interface ColumnDef {
+    export interface IColumnDef {
+        field?: string;
+        width?: any;  //**this can be a string containing a relatively, absolute size units or a number: '30%','54px',45 /*
+        displayName?: string;
+        cellTemplate?: string;
+        enableCellEdit?: boolean;
     }
 
-    export interface FilterOptions {
+    export interface IFilterOptions {
         filterText?: string;
         useExternalFilter?: boolean;
     }
 
-    export interface PagingOptions {
+    export interface IPagingOptions {
         /**  pageSizes: list of available page sizes.  */
         pageSizes?: number[];
         /** pageSize: currently selected page size.  */