A data structure, method and system are provided incorporating a general purpose memory allocator and defensive heap memory manager. This provides an ability to reliably detect various types of memory errors, dynamically enable or disable memory debugging, enhance success of read and write operations using various memory verification techniques. Further, through separation of control information associated with allocated and free chunks of memory from the chunks themselves (separation of metadata from actual data), enhanced protection of vital information about the heap memory layout in general is provided. The heap memory manager uses read, write, and execute protected heap header walls and pool header walls and may, for each pool and memory block, separately use hidden front and back Memory Debug Information Areas (MDIAs) with checksums and well-known signature fields thereby enhancing overall memory management.