While neither Karl Marx nor Thomas Piketty have a great track record when it comes to economic policy prescriptions (Dean Baker's opinion on this might be interesting for people who share much of their world view with all three of these economists), will they teach me to better negotiate based on my "knowledge of my worth"? I rather doubt that they will, given that the punchline of much of their writing is that worker compensation necessarily trends towards the subsistence level over time, r>g, etc. etc. Certainly if the point is to "know your worth" in the sense of being able to negotiate a better compensation, a better source ought to be available.
Separately, it's an interesting turn of events that fairly politicized economists' writings are now recommended reading for computer programmers. The next logical step is a recommendation to join a political party (certainly joing the political party would help one's career in the USSR where Marx was required reading for people entering the professions.)