diff --git a/src/GTPSA.jl b/src/GTPSA.jl
index 590d1381..6b048817 100644
--- a/src/GTPSA.jl
+++ b/src/GTPSA.jl
@@ -113,6 +113,8 @@ export
   translate,
   par,
   scalar,
+  setGTPSA!,
+  getGTPSA,
   
   # Temporaries:
   @FastGTPSA,
@@ -166,6 +168,42 @@ show_eps::Float64 =  0.0                               # Print epsilon
 show_sparse::Bool = false                              # Use sparse monomial print
 show_header::Bool = false                              # Print a header above each TPS
 
+"""
+    setGTPSA!(a::AbstractString, val)
+
+Function to set global variables in GTPSA. Options for `a` are:
+
+- `desc_current::Descriptor` -- defines the `Descriptor` to use when that information is not explicitly (or implicitly in a TPS copy constructor) available, e.g. when calling `TPS(a)` where `a` is not a TPS. This is set each time a new `Descriptor` is defined
+- `show_eps::Float64`        -- defines the value below which the absolute value of a monomial coefficient is NOT printed
+- `show_sparse::Bool`        -- specifies whether the sparse monomial format is used for printing. This is useful for GTPSAs containing a large number of variables and parameters
+- `show_header::Bool`        -- specifies whether or not to print the GTPSA `Descriptor` information above each TPS output
+"""
+function setGTPSA!(a::AbstractString, val)
+  a == "desc_current" && (GTPSA.desc_current = val; return)
+  a == "show_eps"     && (GTPSA.show_eps = val; return)
+  a == "show_sparse"  && (GTPSA.show_sparse = val; return)
+  a == "show_header"  && (GTPSA.show_header = val; return)
+  error("Global variable \"$(a)\" does not exist!")
+end
+
+"""
+    setGTPSA!(a::AbstractString, val)
+
+Function to set global variables in GTPSA. Options for `a` are:
+
+- `desc_current::Descriptor` -- defines the `Descriptor` to use when that information is not explicitly (or implicitly in a TPS copy constructor) available, e.g. when calling `TPS(a)` where `a` is not a TPS. This is set each time a new `Descriptor` is defined
+- `show_eps::Float64`        -- defines the value below which the absolute value of a monomial coefficient is NOT printed
+- `show_sparse::Bool`        -- specifies whether the sparse monomial format is used for printing. This is useful for GTPSAs containing a large number of variables and parameters
+- `show_header::Bool`        -- specifies whether or not to print the GTPSA `Descriptor` information above each TPS output
+"""
+function getGTPSA(a::AbstractString)
+  a == "desc_current" && (return GTPSA.desc_current)
+  a == "show_eps"     && (return GTPSA.show_eps)
+  a == "show_sparse"  && (return GTPSA.show_sparse)
+  a == "show_header"  && (return GTPSA.show_header)
+  error("Global variable \"$(a)\" does not exist!")
+end
+
 # Descriptor outer constructors
 """
     Descriptor(nv::Integer, vo::Integer)::Descriptor
diff --git a/src/show.jl b/src/show.jl
index 85c88a1f..e69d1736 100644
--- a/src/show.jl
+++ b/src/show.jl
@@ -31,6 +31,7 @@ end
 function show(io::IO, d::Descriptor)
   println(io, "GTPSA Descriptor")
   println(io, "-----------------------")
+  d.desc == C_NULL && (println(io, "Null"); return)
   desc = unsafe_load(d.desc)
   show_GTPSA_info(io, desc)
 end