A chromatin adaptor that recognizes specific forms of histones, either modified by a post-translational modification, or the unmodified form. Histone readers have roles in many processes, including in centromere function or in modulating the accessibility of cis-regulatory regions to the transcription machinery. [ http://www.ncbi.nlm.nih.gov/pubmed/11498575 http://www.ncbi.nlm.nih.gov/pubmed/31082667 http://www.ncbi.nlm.nih.gov/pubmed/25688442 http://www.ncbi.nlm.nih.gov/pubmed/34726351 http://www.ncbi.nlm.nih.gov/pubmed/32260176 ]