Peter Clark & Nik Gervae 
Developing Business Applications with OpenStep(TM) [PDF ebook] 

Open Step is the software development environment co-developed by Sun and Next Computers. This book provides the first introduction to Open Step and how it is used to build business applications for Next, Sun, and Windows NT systems. As well as covering the basics, it covers Web Objects (for developing world wide web applications) and the Enterprise Objects framework for developing database applications. No serious Open Step developer will want to be without this book.