diff --git a/src/goto-programs/goto_inline.cpp b/src/goto-programs/goto_inline.cpp
index d57ad3d5c1a..7b6b219e84d 100644
--- a/src/goto-programs/goto_inline.cpp
+++ b/src/goto-programs/goto_inline.cpp
@@ -16,6 +16,13 @@ Author: Daniel Kroening, kroening@kroening.com
 #include "goto_inline_class.h"
 #include "goto_model.h"
 
+/// Inline every function call into the entry_point() function.
+/// Then delete the bodies of all of the other functions.
+/// This is pretty drastic and can result in a very large program.
+/// Caller is responsible for calling update(), compute_loop_numbers(), etc.
+/// \param goto_model: Source of the symbol table and function map to use.
+/// \param message_handler: Message handler used by goto_inlinet.
+/// \param adjust_function: Replace location in inlined function with call site.
 void goto_inline(
   goto_modelt &goto_model,
   message_handlert &message_handler,
@@ -29,6 +36,14 @@ void goto_inline(
     adjust_function);
 }
 
+/// Inline every function call into the entry_point() function.
+/// Then delete the bodies of all of the other functions.
+/// This is pretty drastic and can result in a very large program.
+/// Caller is responsible for calling update(), compute_loop_numbers(), etc.
+/// \param goto_functions: The function map to use.
+/// \param ns : The namespace to use.
+/// \param message_handler: Message handler used by goto_inlinet.
+/// \param adjust_function: Replace location in inlined function with call site.
 void goto_inline(
   goto_functionst &goto_functions,
   const namespacet &ns,
@@ -96,11 +111,14 @@ void goto_inline(
 
 /// Inline all function calls to functions either marked as "inlined" or
 /// smaller than smallfunc_limit (by instruction count).
+/// Unlike the goto_inline functions, this doesn't remove function
+/// bodies after inlining.
+/// Caller is responsible for calling update(), compute_loop_numbers(), etc.
 /// \param goto_model: Source of the symbol table and function map to use.
 /// \param message_handler: Message handler used by goto_inlinet.
 /// \param smallfunc_limit: The maximum number of instructions in functions to
 ///   be inlined.
-/// \param adjust_function: Tell goto_inlinet to adjust function.
+/// \param adjust_function: Replace location in inlined function with call site.
 void goto_partial_inline(
   goto_modelt &goto_model,
   message_handlert &message_handler,
@@ -118,13 +136,16 @@ void goto_partial_inline(
 
 /// Inline all function calls to functions either marked as "inlined" or
 /// smaller than smallfunc_limit (by instruction count).
+/// Unlike the goto_inline functions, this doesn't remove function
+/// bodies after inlining.
+/// Caller is responsible for calling update(), compute_loop_numbers(), etc.
 /// \param goto_functions: The function map to use to find functions containing
 ///   calls and function bodies.
 /// \param ns: Namespace used by goto_inlinet.
 /// \param message_handler: Message handler used by goto_inlinet.
 /// \param smallfunc_limit: The maximum number of instructions in functions to
 ///   be inlined.
-/// \param adjust_function: Tell goto_inlinet to adjust function.
+/// \param adjust_function: Replace location in inlined function with call site.
 void goto_partial_inline(
   goto_functionst &goto_functions,
   const namespacet &ns,
@@ -153,6 +174,9 @@ void goto_partial_inline(
     if(gf_entry.first == goto_functions.entry_point())
     {
       // Don't inline any function calls made from the _start function.
+      // This is so that the convention of __CPROVER_start
+      // calling __CPROVER_initialize is maintained, so these can be
+      // augmented / replaced by later passes.
       continue;
     }
 
@@ -205,11 +229,12 @@ void goto_partial_inline(
   goto_inline.goto_inline(inline_map, false);
 }
 
-/// Inline all function calls made from a particular function
+/// Transitively inline all function calls made from a particular function.
+/// Caller is responsible for calling update(), compute_loop_numbers(), etc.
 /// \param goto_model: Source of the symbol table and function map to use.
 /// \param function: The function whose calls to inline.
 /// \param message_handler: Message handler used by goto_inlinet.
-/// \param adjust_function: Tell goto_inlinet to adjust function.
+/// \param adjust_function: Replace location in inlined function with call site.
 /// \param caching: Tell goto_inlinet to cache.
 void goto_function_inline(
   goto_modelt &goto_model,
@@ -228,12 +253,13 @@ void goto_function_inline(
     caching);
 }
 
-/// Inline all function calls made from a particular function
+/// Transitively inline all function calls made from a particular function.
+/// Caller is responsible for calling update(), compute_loop_numbers(), etc.
 /// \param goto_functions: The function map to use to find function bodies.
 /// \param function: The function whose calls to inline.
 /// \param ns: Namespace used by goto_inlinet.
 /// \param message_handler: Message handler used by goto_inlinet.
-/// \param adjust_function: Tell goto_inlinet to adjust function.
+/// \param adjust_function: Replace location in inlined function with call site.
 /// \param caching: Tell goto_inlinet to cache.
 void goto_function_inline(
   goto_functionst &goto_functions,
diff --git a/src/goto-programs/goto_inline.h b/src/goto-programs/goto_inline.h
index 543ae9fa9d8..c3db270cede 100644
--- a/src/goto-programs/goto_inline.h
+++ b/src/goto-programs/goto_inline.h
@@ -8,6 +8,8 @@ Author: Daniel Kroening, kroening@kroening.com
 
 /// \file
 /// Function Inlining
+/// This gives a number of different interfaces to the function
+/// inlining functionality of goto_inlinet.
 
 #ifndef CPROVER_GOTO_PROGRAMS_GOTO_INLINE_H
 #define CPROVER_GOTO_PROGRAMS_GOTO_INLINE_H
diff --git a/src/goto-programs/goto_inline_class.cpp b/src/goto-programs/goto_inline_class.cpp
index 85dafc27f4c..534c2aaa2f0 100644
--- a/src/goto-programs/goto_inline_class.cpp
+++ b/src/goto-programs/goto_inline_class.cpp
@@ -296,6 +296,8 @@ void goto_inlinet::insert_function_body(
   dest.destructive_insert(target, tmp);
 }
 
+/// Inlines a single function call
+/// Calls out to goto_inline_transitive or goto_inline_nontransitive
 void goto_inlinet::expand_function_call(
   goto_programt &dest,
   const inline_mapt &inline_map,
@@ -441,6 +443,11 @@ void goto_inlinet::get_call(
   arguments=call.arguments();
 }
 
+/// Inline all of the given call locations.
+/// This is the highest-level interface and calls the other goto_inline
+/// \param inline_map : which call locations to inline.
+/// \param force_full : true to break recursion with a SKIP,
+///   false means detecting recursion is an error.
 void goto_inlinet::goto_inline(
   const inline_mapt &inline_map,
   const bool force_full)
@@ -460,6 +467,13 @@ void goto_inlinet::goto_inline(
   }
 }
 
+/// Inline all of the chosen calls in a given function.
+/// This is main entry point for the functionality
+/// \param identifier : the name of the caller function.
+/// \param goto_function : the caller function itself.
+/// \param inline_map : which call locations to inline.
+/// \param force_full : true to break recursion with a SKIP,
+///   false means detecting recursion is an error.
 void goto_inlinet::goto_inline(
   const irep_idt identifier,
   goto_functiont &goto_function,
diff --git a/src/goto-programs/goto_inline_class.h b/src/goto-programs/goto_inline_class.h
index e7bbabdaec1..71a1951b3dc 100644
--- a/src/goto-programs/goto_inline_class.h
+++ b/src/goto-programs/goto_inline_class.h
@@ -6,6 +6,11 @@ Author: Daniel Kroening, kroening@kroening.com
 
 \*******************************************************************/
 
+/// \file
+/// Function Inlining
+/// This is a class that encapsulates the state and functionality needed
+/// to do inline multiple function calls.
+/// goto_inline.h provides a number of more convenient interfaces.
 
 #ifndef CPROVER_GOTO_PROGRAMS_GOTO_INLINE_CLASS_H
 #define CPROVER_GOTO_PROGRAMS_GOTO_INLINE_CLASS_H
@@ -20,6 +25,13 @@ Author: Daniel Kroening, kroening@kroening.com
 class goto_inlinet
 {
 public:
+  /// Sets up the class with the program to operate on.
+  ///
+  /// \param goto_functions : The map of functions to work on
+  /// \param ns : The corresponding namespace
+  /// \param message_handler : Used to log what is being inlined
+  /// \param adjust_function: Replace location in caller location.
+  /// \param caching : cache functions when in transitive mode
   goto_inlinet(
     goto_functionst &goto_functions,
     const namespacet &ns,