That is one of three books from Tkyte:
Expert Oracle One ON One (8i)
Expert Oracle Database Architecture: 9i and 10g Programming Techniques and Solutions (9i/10g)
Effective Oracle By Design
PDF is portable and convenient. Some guys may find the paper book is too heavy to carry. I like to read PDFs.
Tom once said "If you can read through the Concept Manual and able to retain 10% of it, you know more than other 90% Oracle DBAs".Very impressed.