Here is a list of all topics with brief descriptions:

Base Module
Array, Vector and Matrix Classes
Argument Parser	Argument Parser
Basic and Miscellaneous Math Functions
Error Functions
Hyperbolic Functions
Logarithmic and Exponential Functions
Miscellaneous Functions
Numerical Integration	Numerical integration routines
Trigonometric Functions
Bessel Functions
Conversion Functions
Diagonal Matrices and Functions
Error and Warning Handling
Functions on Matrices	Functions on vectors and matrices
IT++ File Format	The IT++ file format
Linear Algebra
Determinant
Inverse Matrix
Matrix Decompositions
Solving Linear Equation Systems
Random Number Generation
Reshaping of Vectors and Matrices
Special Matrices
Timers
Communications Module
Channel Modeling	Communication Channel Models
Digital Modulation
Forward Error Correcting Codes
Interleavers
Miscellaneous Communications Functions
Sequences
Fixed-point Module	Fixed-Point Data Types
Numerical Optimization Module	Numerical optimization routines
Protocols Module
Signal Processing (SP) Module
Deterministic Sources
Fast Independent Component Analysis
Filtering
Polynomial Functions
Resampling Functions
Miscellaneous SP Functions
Transforms
Discrete Cosine Transform (DCT)	One dimensional Dicrete Cosine Transform
Fast Fourier Transform (FFT)	One dimensional fast fourier transform
Fast Hadamard Transform (FHT)
Windowing	Windowing functions
Source Coding Module
Audio
Image Functions and Classes
LPC-related Functions
Source Coding Routines
Statistics Module
Histogram
Miscellaneous Statistics Functions
Mixture of Gaussians (MOG)	Classes and functions for modelling multivariate data as a Mixture of Gaussians
Mexfiles	Conversions between IT++ and Matlab for writing mex-files