Software Methodologies: Recommended titles for readers interested in agile development methodologies include Alistair Cockburn's Agile Software Development and Integrating Agile Development in the Real World. Many of the techniques adopted by agile teams, such as unit testing, automated builds etc are covered in Steve McConnell's excellent Code Complete. For more heavyweight methodologies a good introduction to the RUP is provided by Rational Unified Process Made Easy. There's more to be found on our software methodologies book reviews index
Object Oriented: There are plenty of books that focus on a particular language implementation of objects, but for a very good language independent guide then Object Thinking by David West is recommended. Of the language-specific titles, Objects First With Java stands out as being different in that it is designed specifically for class-room instruction and uses the BlueJ development environment to teach both Java and object-oriented programming. And let's not forget design patterns, with Head First Design Patterns as a great place to start.
Java: The obvious place to look for recommendations is on our Java book reviews index. However for those in too much of a hurry then Thinking In Java, Just Java 2 and Java Examples In A Nutshell are good for programmers making the switch to Java. For those new to programming and who want to go the Java route then take a look at: Objects First With Java, Head First Java, Java How To Program and Beginning Java 2.
C/C++/C#: Anyone wanting to look at C for the first time ought to take a look at Programming In C or Beginning C. For C++ Bruce Eckel's Thinking In C++ is an in-depth title, while C++ Without Fear is a much less demanding read (though not recommended for existing programmers wanting to learn C++). And those wanting to dip their toes in the waters of C# should look for C# Unleashed, Programming C# by Jesse Liberty or Murach's C#.
VB/VBA/VB.NET: For the die-hard Visual Basic 6.0 programmer, or anyone who wants to become one, the book to recommend is obvious: Programming Visual Basic 6.0. There's more choice for VB.NET: Professional VB.NET and VB.NET Primer Plus are both highly recommended. Finally, we mustn't forget that old work-horse VBA (in our case with a bias to Excel), with Excel VBA In Easy Steps aimed squarely at the absolute beginner and The Definitive Guide to Excel VBA aimed at the would-be expert.
Scripting/Dynamic Languages: And before the language lawyers pounce, we mean Perl, Python and Ruby. Our favourite Perl title is Computer Science and Perl Programming, it's a great compendium of interesting stuff. Python beginners are spoilt for choice with Dive Into Python and Learning Python offering great introductions. Also highly recommended is the Python Cookbook, an indispensible resource. Ruby gets a great introudction with Programming Ruby.
XML: It's everywhere and every developer needs to know it. Good place to start is Learning XML. From the programming point of view Java developers should head for Processing XML with Java while a multi-language path is hacked out in XML Primer Plus. Of course there's more on our XML book reviews index
Linux/Unix: For C programmers wanting to develop for Linux or other members of the Unix family then two books stand out above the rest. Linux Programming By Example and Advanced Unix Programming are both recommended. Of course don't forget to take a look at the rest of the Linux book reviews.
Ajax: There's a real rush of books on Ajax, but the TechBookReport favourites include Head Rush Ajax and Ajax In Action.
ASP/JSP: ASP.NET is well-covered by Programming ASP.NET and on the Java side Murach's Java Servlets and JSP gets a recommendation.
Other: As well as XML every programmer ought to learn SQL and regular expressions, covered in SQL In 10 Minutes and Regular Expressions In 10 Minutes respectively. There's plenty more topics of course, but then that's why we've got the full listing on this page to chose from.