Hello again! I'll keep this short as it is getting late over here. Here is a recap of what has been happening. We define new classes with a `deftransactional-class' form. (deftransactional-class foo () ((a :initarg :a :accessor a))) Slots are automatically kept track of. Whenever we read or write to them, the changes are intercepted with the MOP's `slot-value-using-class'. We write it to the current transaction log, to be committed later. Today I worked on composing transactions. I've made them compose sequentially. Alternate composition is a while off. I think I need to make nested transactions possible first. I'll abruptly end now. Remember, to get the latest: darcs get http://common-lisp.net/project/cl-stm or alternatively browse it on the web at: http://common-lisp.net/cgi-bin/darcsweb/darcsweb.cgi?r=cl-stm%20cl-stm;a=sum... Hoan