This is an announcement for the paper "The alternative Daugavet property of $C^*$-algebras and $JB^*$-triples" by Miguel Martin. Abstract: A Banach space $X$ is said to have the alternative Daugavet property if for every (bounded and linear) rank-one operator $T:X\longrightarrow X$ there exists a modulus one scalar $\omega$ such that $\|Id + \omega T\|= 1 + \|T\|$. We give geometric characterizations of this property in the setting of $C^*$-algebras, $JB^*$-triples and their isometric preduals. Archive classification: Functional Analysis; Operator Algebras Mathematics Subject Classification: 46B20, 46L05, 17C65 (primary); 47A12 (secondary) The source file(s), Martin-ADP.tex: 44541 bytes, is(are) stored in gzipped form as 0411555.gz with size 14kb. The corresponding postcript file has gzipped size 69kb. Submitted from: mmartins@ugr.es The paper may be downloaded from the archive by web browser from URL http://front.math.ucdavis.edu/math.FA/0411555 or http://arXiv.org/abs/math.FA/0411555 or by email in unzipped form by transmitting an empty message with subject line uget 0411555 or in gzipped form by using subject line get 0411555 to: math@arXiv.org.