From the Napoleon Series: The Truth About Memoirs by Max Sewell.
This is a most useful guide to the credibility of period memoirs, including unreliable memoirs still being used in publications.
www.napoleon-series.org/research/eyewitness/c_truth.html
The following reference is mentioned in the above article:
Napoleon: The Myth of the Saviour by Jean Tulard
" His notes at the end contain a summary of short opinions on memoires (page 353). He remarks that "memoires are an important mine of information, though often unreliable, it is true." His extraordinary Notes section (pages 353-449) is particularly valuable for a lengthy study of sources."
Amazon.com: Napoleon: The Myth of the Saviour by Jean Tulard (1985-05-30): Libros
Those of us from an engineering/scientific background view all human recollection to be inherently faulty. Even that given honestly at the time is subject to the simple differences in observation points and interpretations. However, just like a good detective bureau, eyewitness testimony, both contemporaneous and historical can be weighted and sifted. Cognitive biases are now well understood by psychologists and the most common ones can be allowed for. When combined with geospatial data and experimental archeology to provide time and motion mechanics a reasonably accurate synthesis of events can be made, within the tolerances required for historical interpretation. This much I have discovered in doing root cause analysis of complex systems. However, technology is arriving fast to assist us in closing the gap. Artificial intelligence and machine learning will be vital tools for the historian of the future.