In general, I think the article gives a compact yet inclusive idea of current state of affairs in crossmodal attention. I feel, however, that like any other review some aspects may be underrepresented. Elaborating a little more on those would add to the feling of completeness.
a. The definition of attention in the introduction in not satisfactory. "Attention refers to those processes that allow for the selective processing of incoming sensory stimuli." Any sensory modality with its filter properties would confirm to this definition. Thus, the definition provided in this introduction needs to be more precise.
b. the section "cross-modal attention and visual dominance" is far to rudimentary. It is ignoring a large part of the literature demonstrating that it is difficult to ignore stimuli from the non-attented modality (e.g. work by Bertelson, Shams, Bresciani, ...). Additionally, there is evidence that the weighting of multisensory information (e.g., dominance of one or the other modality) is not affected by modality-specific attention (Helbig and Ernst, Journal of Vision, 2008).
c. Neural correlates of cross-modal attention: I guess it would be interesting to make a little more about the findings on the expression of multisensory attention in early sensory brain areas (note Macaluso et al., 2001, 2002, etc...); and it would be nice to link this discussion with the comment (already present in the text) about the controversy on whether exogenous crossmodal attention effects and multisensory enhancement effects are one and the same thing or not (McDonal et al,. 2001, Science).
d. The review is completely sweked toward the case of "spatial" crossmodal attention, though the title of the article is "crossmodal attention". I am aware that spatial attention has a big weight in the field, but perhaps mention of non-spatial crossmodal attention phenomena such as the attentional blink (Duncan et al., 1997; Arnell et al., Hein et al., 2002...) , or even cross-modal cueing in time (Correa et al..).
Other than that, I have a couple more specific comments too
1. Introduction: The definition of attention only as a selective process may not be perfectly accurate. I am thinking that some people can consider processes such as arousal, alerting, and so on, as benig attention, but they do no involve selectivity....
2. 3rd paragraph into "Attending to a sensory modality" section. Clarify the meaning of "highe-level" stimulus or else use a more explicit term.... (I do not think that "spatial location" is a higher-level stimulus in the same sense than "identity" is.).
3. "Maintaining crossmodal correspondence following posture change" : Perhaps bring in the recent findings by Azañon & Soto-Faraco (2008). I think it is relevant because A&S-F show that these remappings of information across the senses do indeed occur, and determine the spatial reference frame for the deployment of attention, but they also take some time to set-up. So that one can sometimes find the prevalence of one reference frame or the other depending on the time elapsed after stimulus presentation.
This is a strong and concise review. It covers a lot of ground with authority and presents the state of play in a number a subfields crossmodal attention. It feels rather Spence-centric, but then Spence is associated with so much of the published work. And, as noted by the other reviewer, it is mainly focused on spatial attention. In general, I have no quibble with what is presented, and if it were published as it stands, it would be a good contribution. However, but at the risk of turning this article into an encylopaedia, i believe it could be expanded somewhat and improved.
Work on neural correlates could include, among other things: work by Macaluso, and highlight TMS studies (such as those by chambers 2004/2007) a little more, as they can be very strong in providing causal evidence of neural bases.
There is also work by the Theeuwes group which shows a special role for temporal synchrony in crossmodal orienting (van der Burg 2008/2009). This could be used to expand from the primarily spatial focus. (or another angle on spatial attention, since their studies are about visual search)
Organisation & minor edits: Couldn't para 2 of Introduction be inserted after sentence 2 of para 1? Para 2 deals with definitions (exo/endo attention). Perhaps definitions of overt & covert attention could also go earlier in a definitions section (currently they appear in para 1 of "crossmodal links in spatial attention").
Last sentence of section "Crossmodal attention and visual dominance" could do with a re-write.
Last paragraph of section "crossmodal links in spatial attention" mentions fMRI and TMS studies incredibly briefly -- in one sentence!! I think the overview of this work could be expanded, and possibly could go 5 paras earlier at the end of the "attending to a sensory modality" section (where other neural correlates studies are mentioned).
Last sentence of "crossmodal links in endogenous attention": refer to the specific models in Figure 1 to be clear.
"crossmodal links in exdogenous spatial attention": Para 2, sentence 4, delete "studies have now"
Near the end, teh section "Neural underpinnings of crossmodal spatial attention" could be expanded. Perhaps save the other references to neural studies for an expanded discussion here.
References: a number of papers i expected to find in the references were not there. At the author's discretion, the following could be included: Macaluso, Frith, & Driver 2002
Bonnel & Hafter 1998
Rees, Frith & Lavie 2001; Ferlazzo et al 2002 Larsen et al 2003)
(Triesman & Davies 1973