diff --git a/R/Start.R b/R/Start.R
index 2854453fc65ee7b90c39a639dda28d66a1a6b9f3..288524a6b56687e1cfadc390aa95ff53aff9e046 100644
--- a/R/Start.R
+++ b/R/Start.R
@@ -18,7 +18,8 @@ Start <- function(..., # dim = indices/selectors,
                   apply_indices_after_transform = FALSE, 
                   pattern_dims = NULL,
                   metadata_dims = NULL, 
-                  selector_checker = SelectorChecker, 
+                  selector_checker = SelectorChecker,
+                  retrieve = FALSE, 
                   num_procs = NULL, silent = FALSE, debug = FALSE) {
                   #, config_file = NULL
                   #dictionary_dim_names = ,
@@ -461,6 +462,11 @@ Start <- function(..., # dim = indices/selectors,
   }
   transform_extra_cells <- round(transform_extra_cells)
 
+  # Check retrieve
+  if (!is.logical(retrieve)) {
+    stop("Parameter 'retrieve' must be TRUE or FALSE.")
+  }
+
   # Check num_procs
   if (!is.null(num_procs)) {
     if (!is.numeric(num_procs)) {
@@ -2251,6 +2257,9 @@ print("-> PROCEEDING TO CROP VARIABLES")
   new_dims <- .MergeArrayDims(dim(array_of_files_to_load), total_inner_dims)
   final_dims <- pmax(new_dims[[1]], new_dims[[2]])[dim_names]
 
+  # The following several lines will only be run if retrieve = TRUE
+  if (retrieve) {
+
   ########## CREATING THE SHARED MATRIX AND DISPATCHING WORK PIECES ###########
   # TODO: try performance of storing all in cols instead of rows
   # Create the shared memory array, and a pointer to it, to be sent
@@ -2553,6 +2562,8 @@ print("-> WORK PIECES BUILT")
     array_of_not_found_files <- NULL
   }
 
+  } # End if (retrieve)
+
   # Replace the vars and common vars by the transformed vars and common vars
   for (i in 1:length(dat)) {
     if (length(names(transformed_vars[[i]])) > 0) {
@@ -2572,19 +2583,38 @@ print(str(transformed_vars))
 print("-> THE PICKED VARS:")
 print(str(picked_vars))
 }
-  if (!silent) {
-    .message("Successfully retrieved data.")
-  }
 
   file_selectors <- NULL
   for (i in 1:length(dat)) {
     file_selectors[[dat[[i]][['name']]]] <- dat[[i]][['selectors']][which(names(dat[[i]][['selectors']]) %in% found_file_dims[[i]])]
   }
-  list(Data = data_array, 
-       Variables = c(list(common = picked_common_vars), picked_vars),
-       Files = array_of_files_to_load, 
-       NotFoundFiles = array_of_not_found_files,
-       FileSelectors = file_selectors)
+  if (retrieve) {
+    if (!silent) {
+      .message("Successfully retrieved data.")
+    }
+    structure(
+      list(Data = data_array, 
+           Variables = c(list(common = picked_common_vars), picked_vars),
+           Files = array_of_files_to_load, 
+           NotFoundFiles = array_of_not_found_files,
+           FileSelectors = file_selectors),
+      class = 'startR_cube'
+    )
+  } else {
+    if (!silent) {
+      .message("Successfully discovered data dimensions.")
+    }
+    startR_call <- match.call()
+    startR_call[['retrieve']] <- TRUE
+    structure(
+      list(Dimensions = final_dims,
+           Variables = c(list(common = picked_common_vars), picked_vars),
+           ExpectedFiles = array_of_files_to_load,
+           FileSelectors = file_selectors,
+           StartRCall = startR_call),
+      class = 'startR_header'
+    )
+  }
 }
 
 # This function is the responsible for loading the data of each work
diff --git a/man/Start.Rd b/man/Start.Rd
index d56d23f58a6718729f18e08835fffcaaddf12b7a..bda85a8c6b0dc4b4aa8b62fc53d5427e52de06fd 100644
--- a/man/Start.Rd
+++ b/man/Start.Rd
@@ -38,6 +38,7 @@ Start(...,
       pattern_dims = NULL, 
       metadata_dims = NULL, 
       selector_checker = SelectorChecker, 
+      retrieve = FALSE,
       num_procs = NULL, 
       silent = FALSE, 
       debug = FALSE)
@@ -344,6 +345,9 @@ It expects to receive a vector of character strings with the names of the file d
   }
   \item{selector_checker}{
 Function used internaly by \code{Start()} to translate a set of selectors (values for a dimension associated to a coordinate variable) into a set of numeric indices. It takes by default \code{SelectorChecker} and, in principle, it should not be required to change it for customized file formats. The option to replace it is left open for more versatility. See the code of \code{SelectorChecker} for details on the inputs, functioning and outputs of a selector checker. 
+  }
+  \item{retrieve}{
+Logical value telling whether to retrieve the data defined in the \code{Start} call or to explore only its dimension lengths and names, and the values for the file and inner dimensions. Takes FALSE by default.
   }
   \item{num_procs}{
 Number of processes to be created for the parallel execution of the retrieval / transformation / arrangement of the multiple involved files in a call to \code{Start()}. Takes by default the number of available cores (as detected by \code{detectCores()} in the package 'future').
@@ -352,13 +356,14 @@ Number of processes to be created for the parallel execution of the retrieval /
 Boolean flag, whether to display progress messages (FALSE; default) or not (TRUE).
   }
   \item{debug}{
-Whether to return detailed messages on the progress and operations in a \code{Start()} call (TRUE) or not (FALSE; default).
+Whether to return detailed messages on the progress and operations in a \code{Start} call (TRUE) or not (FALSE; default).
   }
 }
 \details{
 Check \href{https://earth.bsc.es/gitlab/es/startR}{the startR website} for more information.
 }
 \value{
+If \code{retrieve = TRUE} the involved data is loaded into RAM memory and an object of the class 'startR_cube' with the following components is returned:\cr
   \item{Data}{
 Multidimensional data array with named dimensions, with the data values requested via \dots and other parameters. This array can potentially contain metadata in the attribute 'variables'.
   }
@@ -374,6 +379,22 @@ Array with the same shape as \code{$Files} but with \code{NULL} in the positions
   \item{FileSelectors}{
 Multidimensional character string array with named dimensions, with the same shape as \code{$Files} and \code{$NotFoundFiles}, which contains the components used to build up the paths to each of the files in the data sources.
   }
+If \code{retrieve = FALSE} the involved data is not loaded into RAM memory and an object of the class 'startR_header' with the following components is returned:\cr
+  \item{Dimensions}{
+Named vector with the dimension lengths and names of the data involved in the \code{Start} call.
+  }
+  \item{Variales}{
+Named list of 1 + N components, containing lists of retrieved variables (as requested in \code{return_vars}) common to all the data sources (in the 1st component, \code{$common}), and for each of the N dara sources (named after the source name, as specified in \dots, or, if not specified, \code{$dat1}, \code{$dat2}, ..., \code{$datN}). Each of the variables are contained in a multidimensional array with named dimensions, and potentially with the attribute 'variables' with additional auxiliary data.
+  }
+  \item{Files}{
+Multidimensonal character string array with named dimensions. Its dimensions are the file dimensions (as requested in \dots). Each cell in this array contains a path to a file to be retrieved (which may exist or not).
+  }
+  \item{FileSelectors}{
+Multidimensional character string array with named dimensions, with the same shape as \code{$Files} and \code{$NotFoundFiles}, which contains the components used to build up the paths to each of the files in the data sources.
+  }
+  \item{StartRCall}{
+List of parameters sent to the \code{Start} call, with the parameter \code{retrieve} set to \code{TRUE}. Intended for calling in order to retrieve the associated data a posteriori with a call to \code{do.call}.
+  }
 }
 \author{
 History:\cr