Not just a (very) good book for component development issues, this book is for anyone who is looking for the extra insight that is usually lacking in the more general texts. I particularly liked it for the way it advocates a very rational (note the small 'r') common-sense approach in terms of building anything with OOP, applications as well as components. In all, very readable, yet very good on the relevant technical detail. Key sections are on the VCL architecture, Property Streaming, RTTI, (Windows) Message issues and the open tools API. For best practise component development, I reckon this is the best place to start.