MIDI PhraseBook is an algorithmic composition tool for Windows. Generate and play musical phrases based on the parameters you choose, such as key, tempo and duration. Once generated, MIDI files can be saved for use in other apps such as DAWs. PhraseBook is simple and fun but has powerful functionality. It works with the built-in Microsoft GS Wavetable synth, or with external hardware MIDI devices. It can even work with Virtual Instruments with some creative routing. Global composition parameters include key signature, time signature, tempo in BPM, and number of measures. It supports two instruments, either two channels on a MIDI device or two MIDI devices. Each instrument has its own unique settings for octaves, velocity, note density and more. Generated phrases can be played once or looped, through the Windows default sound device. You can select all the options you want, or you can select the randomize option and see what ensues. Three levels of randomization are provided, to produce results ranging from tame to … interesting. A free trial version limits some functionality and should be useful in determining whether the application supports your interests and your environment. The trial version (as well as the full version) lets you export or drag MIDI data to other apps so you can be certain PhraseBook is compatible with your favorite programs. The full version lets you save the parameters of your favorite phrases for future use, lets you customize each level of randomization, lets you set friendly names for your MIDI devices and also supports longer compositions. The MIDI PhraseBook is the first release of the MIDI Playground series of apps from NaiveSoft.