The stable C and O isotopic record has been used as a palaeoenvironmental tool since the 1950s. While the recognition of post depositional alteration (diagenesis) upon the signal was recognized almost immediately, the importance of such alteration has been increasingly ignored, to the point where signals which are suspiciously diagenetic are being interpreted as reflecting changes in the global carbon budget. So that we do not through the ‘..baby out with the bathwater ..’ in this presentation I will critically examine some of the criteria used to establish the integrity of carbonate as paleoenvironmental tools, and present new interpretations of C , O, B, and S isotopic patterns in carbonates.