Hi there, apparently for association lists, it is possible to have 'new' entries in front of the list 'shadow' old entries. See https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node153.html However, the Alexandria function alists-hash-table does not account for this behavior when transforming an a-list to a hash-table. There is no checking for duplicate keys in an a-list, resulting in the 'older' entries finding their way in the resulting hash-table. Similar is for p-lists and the plist-hash-table function, though I found contradicting statements whether duplicate keys are allowed for those. At least the hyperspec explains that in case of multiple pairs, the first key/value pair defines the property. See http://www.lispworks.com/documentation/HyperSpec/Body/26_glo_p.htm#property_... CL-USER> alist ((:ONE 1) (:TWO 2) (:ONE :SURPRISE)) CL-USER> (assoc :one alist) (:ONE 1) CL-USER> (gethash :one (alexandria:alist-hash-table alist)) (:SURPRISE) T Thanks for your consideration! Kind Regards, Christoph Arenz