Anne Shaver-Crandell, Cambridge Introduction to Art: The Middle Ages is an excellent starting-point. Clear and helpful chapter on Romanesque.
George Zarnecki, Romanesque, has chapters on the different media: Architecture, Sculpture, Metalwork, Ivories, Stained Glass, Wall Painting, Book Illumination. The author takes us through the key features of each of these, and wears his enormous learning lightly. As with many older art books, this one challenges the reader by having illustrations on a different page from the text, so there is a good deal of flicking around which interrupts the reading. Well, we just have to get over it. The points Zarnecki makes in capsules about individual images (capital sculptures, for example) are outstanding.
Henri Focillon, The Art of the West 1: The Romanesque is a classic of art history. First published in 1938, it shows the author's appetite for dealing with whole cultures, whole centuries, looking for deep principles which help us to understand the individual object. Focillon writes wonderfully, in a style quite different to most approved art history. Of Romanesque imagery - bestiaries, strange distorted sculptures - he says: 'It seems, not the created world, but the dream of God on the eve of the Creation, a terrible first-draft of his plan'. Thoughts like that put a smile on your face and transform the act of seeing. Plenty to be learned here - as far as I can tell, it's not overly dated - and inspirational too.
A quick mention for two books which cover a wider period than those above: John Beckwith, Early Medieval Art and C R Dodwell, The Pictorial Art of the West, 800-1200. Best read in that order. That's a long enough list for now.