In the Castle of My Skin by George Lamming (1953) is the essential Barbadian novel — a semi-autobiographical coming-of-age story set in a rural village in the 1930s and 40s, tracing the end of colonial Barbados through a boy's eyes. It remains one of the great Caribbean novels in English.
The Pleasures of Exile by George Lamming (1960) is part essay, part memoir, part literary criticism, and entirely worth reading if you want to understand how Barbadians and other Caribbean writers think about colonialism, language, and identity. Dense but rewarding.
Barbadian Popular Music and the Politics of Caribbean Culture by Curwen Best examines Barbadian music culture from tuk to calypso to soca — the first academic work devoted exclusively to the subject. Useful background if you're attending Crop Over.
Parish behind God's Back: The Changing Culture of Rural Barbados by George and Sharon Gmelch is an anthropological study of a rural Barbadian village, updated across several decades. It gives a grounded picture of how life has changed (and what hasn't) away from the tourist coast.
Natural Rebels: A Social History of Enslaved Black Women in Barbados by Hilary McD. Beckles is a landmark work of Caribbean history, recovering the specific experiences of enslaved women in the plantation economy. The history of slavery is inescapable in Barbados — this book is one of the better ways to engage with it seriously.
For practical travel, the Rough Guide to Barbados remains a solid reference for orientation, beaches, and accommodation.