Ask HN: Recommendations for malware analysis books

I'm currently a sysadmin, with limited c/python programming (mostly scripting if im honest) however recently my job has been dealing more and more with very nuanced malware threats to our infrastructure (we are a web hosting company). I'd like to be able to understand these threats better on a fundamental level, and as with anything i'd like to get some textbooks to help round out whatever practical things i attempt in a VM. What are the good "go to" texts for this particular area of security?